25.26   PASPALUM L.
Charles M. Allen
David W. Hall

Plants annual or perennial; cespitose, rhizomatous, or stoloniferous. Culms 3-400 cm, erect, spreading or prostrate, sometimes trailing for 200+ cm. Sheaths open; auricles sometimes present; ligules membranous. Inflorescences terminal, sometimes also axillary, panicles of 1-many spikelike branches, these digitate or racemose on the rachis, spreading to erect, 1 or more branches completely or partially hidden in the sheaths in some species; branch axes flattened, usually narrowly to broadly winged, usually terminating in a spikelet, sometimes extending beyond the distal spikelet but never forming a distinct bristle; disarticulation below the glumes. Spikelets subsessile to shortly pedicellate, plano-convex, rounded to acuminate, dorsally compressed, not subtended by bristles or a ring like callus, solitary or paired (1 spikelet of the pair reduced in some species), in 2 rows along 1 side of the branches, with 2 florets, first rachilla segment not swollen, upper glumes and upper lemmas adjacent to the branch axes; lower florets sterile; upper florets sessile or stipitate, bisexual, acute or rounded. Lower glumes absent or present only on some spikelets of each branch, without veins or 1-veined, unawned; upper glumes and lower lemmas subequal, membranous, apices rounded, unawned; lower paleas absent or rudimentary; upper lemmas convex, indurate, smooth to slightly rugose, stramineous to dark brown, margins scarious, involute, clasping the paleas; upper paleas indurate, smooth to slightly rugose, stramineous to dark brown. Caryopses orbicular to elliptical, plano-convex or flattened, white, yellow, or brown. x = 10, 12. Name from the Greek paspalos, a kind of millet.

Paspalum includes 300-400 species, most of which are native to the Western Hemisphere. Forty-three species are found in the Flora region; twenty-four are native. Paspalum scrobiculatum is grown as a grain in India, and several species are grown as forage plants. There are also many weedy species in the genus.

Nineteen of the species growing in the Flora region are introduced, and some of them are weedy. Because weeds are under-represented in most herbaria, the distribution maps of such species probably understate their prevalence.


SELECTED REFERENCES Banks, D.J. 1966. Taxonomy of Paspalum setaceum (Gramineae). Sida 2:269-284; COTECOCA (Comisión Técnico Consultiva de Coeficientes de Agostadero). 2000. Las Graminéas de México, vol. 5. Secretaria de Agricultura, Ganaderia y Desarrollo Rural, México, D.F., México. 466 pp.; Pohl, R.W. and G. Davidse. 1994. Paspalum L. Pp. 335-352 in G. Davidse, M. Sousa S., and A.O. Chater (eds.). Flora Mesoamericana, vol. 6: Alismataceae a Cyperaceae. Universidad Nacional Autónoma de México, Instituto de Biología, México, D.F., México. 543 pp.

1
Spikelets solitary, not associated with a naked pedicel or rudimentary spikelets (2)
Spikelets paired, if only 1 spikelet functional, a naked pedicel or rudimentary, non-functional spikelet present (12)
2
Panicles with 1-70 branches, if more than 1, the branches racemosely arranged (3)
Panicles usually composed of a terminal pair of branches, sometimes with 1(-5) additional branches below the terminal pair (7)
3
Branches 7-70, disarticulating at maturity, the axes extending beyond the distal spikelets ..... 1. P. repens
Branches 1-6, persistent, terminating in a spikelet (4)
4
Upper florets olive to dark brown ..... 2. P. scrobiculatum
Upper florets pale to stramineous (5)
5
Axes of panicle branches 0.6-1.3 mm wide ..... 3. P. laeve
Axes of panicle branches 1.8-3.3 mm wide (6)
6
Spikelets 1.7-2.1 mm long; upper lemmas glabrous throughout ..... 4. P. dissectum
Spikelets 3.2-4 mm long; upper lemmas with a few short hairs at the apices ..... 5. P. acuminatum
7
Upper glumes pilose on the margins or shortly pubescent on the back (8)
Upper glumes glabrous (9)
8
Spikelets 1.3-1.9 mm long; upper glumes pilose along the margins ..... 6. P. conjugatum
Spikelets 2.4-3.2 mm long; upper glumes sparsely short pubescent on the back ..... 7. P. distichum
9
Spikelets elliptic, their apices acute to acuminate (10)
Spikelets ovate to broadly elliptic, their apices obtuse to broadly acute (11)
10
Plants rhizomatous, not appearing cespitose; usually in brackish to salt marsh habitats ..... 8. P. vaginatum
Plants shortly rhizomatous but appearing cespitose; usually in disturbed inland habitats ..... 9. P. almum
11
Spikelets 2.5-4 mm long; leaf blades flat or conduplicate ..... 10. P. notatum
Spikelets 1.9-2.3 mm long; leaf blades flat ..... 11. P. minus
12
Spikelets 1-1.3 mm long (13)
Spikelets 1.3-4.1 mm long (14)
13
Panicle branches 2-6; spikelets elliptic to elliptic-obovate, appressed to the branch axes ..... 12. P. blodgettii
Panicle branches 18-50; spikelets ovate, diverging from the branch axes ..... 13. P. paniculatum
14
Margins of upper glumes and lower lemmas ciliate-lacerate and winged or pilose (15)
Margins of upper glumes and lower lemmas neither ciliate-lacerate nor winged, glabrous or pubescent, if pubescent then the hairs not pilose, often glandular, papillose-based, or wrinkled (17)
15
Upper glumes and lower lemmas ciliate-lacerate, winged ..... 14. P. fimbriatum
Upper glumes and lower lemmas pilose (16)
16
Panicle branches 2-7; spikelets 2.3-4 mm long ..... 15. P. dilatatum
Panicle branches (4)10-30; spikelets 1.8-2.8 mm long ..... 16. P. urvillei
17
Upper florets olive to dark brown (18)
Upper florets white, stramineous, or golden brown (28)
18
Plants aquatic, the culms decumbent, rooting at the nodes; lower glumes often present ..... 17. P. modestum
Plants not aquatic or, if aquatic, the culms erect; lower glumes absent (19)
19
Panicle branches 10-28 or more (20)
Panicle branches 1-10(28) (22)
20
Plants annual; axes of panicle branches broadly winged, wings about as wide as the central portion ..... 18. P. boscianum
Plant perennial; axes of panicle branches narrowly winged, wings narrower than the central portion (21)
21
Axes of panicle branches 1-1.7 mm wide; spikelets 1.8-2.4 mm wide ..... 19. P. virgatum
Axes of panicle branches 0.5-1.2 mm wide; spikelets 1.1-1.8 mm wide ..... 20. P. conspersum
22
Plants annual (23)
Plants perennial (24)
23
Spikelets 1.3-1.8 mm wide, broadly elliptical to orbicular, glabrous; panicles with 1-10(28) branches, the axes 0.7-2.3 mm wide ..... 18. P. boscianum
Spikelets 1.7-2.4 mm wide, broadly obovate, shortly pubescent; panicles with 1-5 branches, the axes 0.8-1.3 mm wide ..... 21. P. convexum
24
Plants cespitose, rhizomes sometimes present but not well-developed; culms 100-200 cm tall, stout; panicle branches ascending, divaricate, or reflexed (25)
Plants not cespitose, rhizomatous; culms 10-150 cm tall, varying in thickness; panicle branches ascending (26)
25
Leaf blades 7-18 mm wide ..... 20. P. conspersum
Leaf blades 2.5-4 mm wide ..... 22. P. plicatulum
26
Rhizomes short, indistinct ..... 22. P. plicatulum
Rhizomes long, evident (27)
27
Plants aquatic; upper florets chestnut brown ..... 23. P. wrightii
Plants not aquatic; upper florets dark brown ..... 24. P. nicorae
28
Lower lemmas with well-developed ribs over the veins; upper glumes absent ..... 25. P. malacophyllum
Lower lemmas not ribbed over the veins; upper glumes present (29)
29
Panicles with 15-100 branches (30)
Panicles with 1-15 branches (33)
30
Plants annual; upper glumes and lower lemmas rugose ..... 26. P. racemosum
Plants perennial; upper glumes and lower lemmas smooth (31)
31
Plants rhizomatous, not cespitose; branch axes 0.9-1.2 mm wide; panicle branches often arcuate ..... 27. P. intermedium
Plants cespitose, not rhizomatous; branch axes 0.3-0.6 mm wide; panicle branches straight (32)
32
Panicle branches spreading to reflexed (rarely ascending); leaf blades 10-23 mm wide; axes of panicle branches 0.3-0.4 mm wide ..... 28. P. coryphaeum
Panicle branches erect to ascending; leaf blades 4.9-6.1 mm wide; axes of panicle branches 0.5-0.6 mm wide ..... 29. P. quadrifarium
33
Spikelet pairs not imbricate; lower glumes usually present ..... 30. P. bifidum
Spikelet pairs imbricate; lower glumes absent or present (34)
34
Spikelets 1.3-2.5 mm long (35)
Spikelets 2.5-4.1 mm long (46)
35
Upper glumes, usually also the lower lemmas, shortly pubescent (36)
Upper glumes and lower lemmas glabrous (40)
36
Lower glumes present ..... 31. P. langei
Lower glumes absent (37)
37
Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath ..... 32. P. setaceum
Panicles all terminal (38)
38
Leaf blades involute; culms 80-110 cm tall ..... 33. P. laxum
Leaf blades flat; culms 20-75 cm tall (39)
39
Spikelets 1.3-2 mm long, 0.7-1 mm wide, elliptic; upper glumes and lower lemmas 5-veined; culm bases swollen ..... 34. P. caespitosum
Spikelets 2-2.5 mm long, 1.4-1.6 mm wide, ovate; upper glumes and lower lemmas 3-veined; culm bases not swollen ..... 35. P. virletii
40
Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath ..... 32. P. setaceum
Panicles all terminal (41)
41
Upper panicle branches erect ..... 36. P. monostachyum
Upper panicle branches spreading to ascending (42)
42
Leaf blades mostly involute; plants of sandy or rocky areas, usually on the coast ..... 37. P. pleostachyum
Leaf blades mostly flat; plants of inland areas or, if coastal, then in marshy areas (43)
43
Upper glumes and lower lemmas 3-veined (44)
Upper glumes and lower lemmas 5-veined (45)
44
Leaf blades usually conduplicate, 2.2-8.3 mm wide ..... 39. P. praecox
Leaf blades usually flat, 5-10 mm wide ..... 35. P. virletii
45
Axes of panicle branches 0.2-0.5 mm wide; ligules 0.2-0.4 mm long ..... 34. P. caespitosum
Axes of panicle branches 1.5-2 mm wide; ligules 2.2-4.7 mm long ..... 38. P. lividum
46
Upper glumes, and usually lower lemmas, pubescent (47)
Upper glumes, and usually lower lemmas, glabrous (49)
47
Lower glumes present ..... 31. P. langei
Lower glumes absent (48)
48
Leaf blades 2-5 mm wide; upper glumes and lower lemmas abundantly pubescent, most hairs longer than 0.1 mm; spikelets elliptic ..... 40. P. hartwegianum
Leaf blades 4-18 mm wide; upper glumes and lower lemmas glabrous or sparsely pubescent, the hairs shorter than 0.1 mm; spikelets obovate to elliptic ..... 41. P. pubiflorum
49
Upper florets golden brown (50)
Upper florets stramineous to pale, but not golden brown (52)
50
Plants not rhizomatous; culms decumbent and rooting at the lower nodes; spikelets 1.3-1.6 mm wide; lower lemmas 5-7-veined; lower glumes often present ..... 17. P. modestum
Plants rhizomatous; culms erect, not rooting at the lower nodes; spikelets 1.9-3.1 mm wide; lower lemmas 3-veined (51)
51
Panicle branches 1-6; upper glumes 5-veined; leaf blades 3-18 mm wide ..... 42. P. floridanum
Panicle branches 1-3; upper glumes 3-veined; leaf blades 3-4 mm wide ..... 43. P. unispicatum
52
Terminal panicle branches erect (53)
Terminal panicle branches spreading to ascending (54)
53
Blades involute; upper glumes 1-veined ..... 36. P. monostachyum
Blades flat; upper glumes 3-veined ..... 43. P. unispicatum
54
Spikelets 2.2-2.6 mm long (55)
Spikelets 2.6-4.1 mm long (56)
55
Spikelets 1.2-1.5 mm wide, elliptic to obovate ..... 38. P. lividum
Spikelets 2-2.8 mm wide, orbicular to suborbicular ..... 39. P. praecox
56
Plants decumbent, rooting at the lower nodes, not rhizomatous; spikelets obovate to elliptic ..... 41. P. pubiflorum
Plants rhizomatous, neither decumbent nor rooting at the lower nodes; spikelets orbicular to elliptic (57)
57
Spikelets 2.1-3.1 mm long, 2-2.8 mm wide, orbicular to suborbicular; upper glumes 3-veined; leaf blades conduplicate ..... 39. P. praecox
Spikelets 2.9-4.1 mm long, 1.9-3.1 mm wide, suborbicular to elliptic; upper glumes 5-veined; leaf blades flat ..... 42. P. floridanum


1.   Paspalum repens P.J. Bergius
Water Paspalum

Plants annual; aquatic, floating or rhizomatous. Culms 4-55 cm, erect; nodes pubescent. Sheaths glabrous or pubescent; ligules 1-4 mm; blades 10-40 cm long, 8-22 mm wide, flat, glabrous or sparsely pubescent. Panicles terminal, with (7)20-70 racemosely arranged branches; branches 1.2-9.5 cm, diverging to spreading, occasionally arcuate, disarticulating at maturity; branch axes 0.7-1.5 mm wide, broadly winged, glabrous, margins scabrous, extending beyond the distal spikelet. Spikelets 1.1-1.9 mm long, 0.5-0.8 mm wide, solitary, appressed to the branch axes, elliptic, pubescent, white. Lower glumes absent; upper glumes and lower lemmas veinless; upper florets white. Caryopses 0.8-0.9 mm, translucent, white. 2n = 20.

Paspalum repens is a native species that grows along the edges of lakes, streams, and roadside ditches in the southeastern United States. Its range extends through tropical America to Peru, Bolivia, and Argentina.


2.   Paspalum scrobiculatum L.
Indian Paspalum

Plants annual. Culms 10-150 cm, erect or decumbent; nodes glabrous. Sheaths glabrous; ligules 0.3-1.2 mm, often with a row of hairs behind them; blades 5-30 cm long, 2-8(12) mm wide, flat, usually glabrous. Panicles terminal, with 1-5 digitately or racemosely arranged branches; branches 3-10 cm, diverging to spreading, persistent; branch axes 1.5-3 mm wide, broadly winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 1.8-3.2 mm long, 2-2.3 mm wide, solitary, diverging from the branch axes, ovate, glabrous, olive green to dark, glossy brown. Lower glumes absent; upper glumes as long as the lower lemmas, 5-7-veined; lower lemmas 3-5-veined; upper florets 2.5-3 mm long, 1.4-1.8 mm wide, dark glossy brown. Caryopses 1.1-1.5 mm, nearly orbicular. 2n = 20, 40, 60, 120.

Paspalum scrobiculatum is native to India. It has been found growing in widely scattered disturbed areas of the southeastern United States, possibly as an escape from cultivation. It is grown as a cereal (Kodo) in India.


3.   Paspalum laeve Michx.
Field Paspalum

Plants perennial; shortly rhizomatous. Culms 40-120 cm, erect; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1.5-3.8 mm; blades to 37 cm long, 2-9.3 mm wide, flat, glabrous or pubescent. Panicles terminal, with 1-6 racemosely arranged branches; branches 2-10.9 cm, diverging to spreading (rarely erect), persistent; branch axes 0.6-1.3 mm wide, glabrous, margins scabrous, terminating in a spikelet. Spikelets 2.3-3.3 mm long, 2-2.7 mm wide, solitary, appressed to the branch axes, elliptic to obovate or nearly orbicular, glabrous, stramineous. Lower glumes absent; upper glumes 3-veined, lower lemmas 5-veined; upper florets pale to stramineous. Caryopses about 2 mm, white to yellow-brown. 2n = 20, 58, 70, 80.

Paspalum laeve is restricted to the eastern United States. It grows at the edges of forests and in disturbed areas.


4.   Paspalum dissectum (L.) L.
Mudbank Paspalum

Plants perennial; rhizomatous. Culms 10-50 cm, decumbent; nodes glabrous or pubescent. Sheaths glabrous; ligules 2-2.5 mm; blades to 12 cm long, 1.3-4.8 mm wide, flat. Panicles terminal, with 2-6 racemosely arranged branches; branches 1.3-5.3 cm, diverging to erect, often arcuate, persistent; branch axes 1.8-3 mm wide, broadly winged, usually conduplicate, glabrous, margins scabrous, terminating in a spikelet. Spikelets 1.7-2.1 mm long, 1.1-1.4 mm wide, solitary, appressed to the branch axes, elliptic to ovate, glabrous, stramineous. Lower glumes absent; upper glumes and lower lemmas 5-veined; upper florets stramineous, lemmas glabrous throughout. Caryopses 1-1.3 mm, white. 2n = 40, 60.

Paspalum dissectum grows at the edges of lakes, ponds, rice fields, and wet roadside ditches. It is native to the eastern portion of the contiguous United States and Cuba.


5.   Paspalum acuminatum Raddi
Brook Paspalum, Canoegrass

Plants perennial; rhizomatous. Culms 30-100 cm, strongly decumbent, upright portion usually not standing more than 20 cm tall, much branched; nodes glabrous. Sheaths glabrous; ligules 1-2.4 mm; blades to 7 cm long, 3-6.5 mm wide, flat. Panicles terminal, with 2-5 racemosely arranged branches; branches 2-6 cm, diverging, persistent; branch axes 2-3.3 mm wide, broadly winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 3.2-4 mm long, 1.6-1.7 mm wide, solitary, appressed to the branch axes, elliptic, abruptly pointed, stramineous. Lower glumes absent; upper glumes and lower lemmas glabrous, 5-veined; upper florets stramineous, lemmas with a few minute hairs at the apices. Caryopses 2-3 mm, white. 2n = 40.

Paspalum acuminatum grows at the edges of lakes, ponds, rice fields, and wet roadside ditches. It is native to the Americas, with a range that extends from the southern United States to Argentina.


6.   Paspalum conjugatum P.J. Bergius
Sour Paspalum

Plants perennial; stoloniferous. Culms 15-80 cm, erect; nodes glabrous. Sheaths glabrous, pubescent distally; ligules 0.5-0.8 mm; blades 7-23 cm long, 1.5-8 mm wide, flat. Panicles terminal, usually composed of a pair of branches, a third branch sometimes present below the terminal pair; branches 2.5-12.7 cm, diverging to spreading, often arcuate, persistent; branch axes 0.2-0.8 mm wide, glabrous, margins scabrous, terminating in a reduced spikelet. Spikelets 1.3-1.9 mm long, 0.8-1.1 mm wide, solitary, appressed to the branch axes, ovate, stramineous. Lower glumes absent; upper glumes pilose on the margins, veinless or 2-3-veined; lower lemmas glabrous, veinless or 2-3-veined; upper florets whitish to golden yellow. Caryopses 0.9-1.1 mm, white to yellow. 2n = 18, 20, 40, 80.

Paspalum conjugatum is native to tropical and subtropical regions of both the Western and Eastern hemispheres. It grows in disturbed areas and at the edges of forests, and is sometimes used as a lawn grass.


7.   Paspalum distichum L.
Knotgrass, Thompsongrass

Plants perennial; rhizomatous or cespitose. Culms 5-65 cm, erect; nodes glabrous. Sheaths glabrous, sparsely long pubescent distally; ligules 1-2 mm; blades to 14 cm long, 1.8-11.5 mm wide, flat or conduplicate, glabrous or pubescent, apices involute. Panicles terminal, usually composed of a digitate pair of branches, a third branch sometimes present below; branches 1.4-7 cm, diverging, often arcuate; branch axes 1.2-2.2 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 2.4-3.2 mm long, 1.1-1.6 mm wide, solitary (rarely paired), appressed to the branch axes, broadly elliptic, stramineous, sometimes partially purple. Lower glumes absent or, if present, to 1 mm and triangular; upper glumes sparsely and shortly pubescent on the back, 3-veined; lower lemmas glabrous, 3-veined; upper florets stramineous. Caryopses 1.9-2.1 mm, yellow. 2n = 20, 30, 40, 48, 60, 61.

Paspalum distichum grows on the edges of lakes, ponds, rice fields, and wet roadside ditches. It is native in warm regions throughout the world, being most abundant in humid areas. In the Western Hemisphere, it grows from the United States to Argentina and Chile.


8.   Paspalum vaginatum Sw.
Seashore Paspalum

Plants perennial; rhizomatous and/or stoloniferous. Culms 10-79 cm, erect; nodes glabrous. Sheaths glabrous, sparsely long pubescent distally; ligules 1-2 mm; blades 10-19 cm long, 1.4-8 mm wide, flat or conduplicate, glabrous or pubescent, apices involute. Panicles terminal, usually composed of a digitate pair of branches, a third branch sometimes present below; branches 1.1-7.9 cm, diverging to erect; branch axes 0.4-1.4 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 3-4.5 mm long, 1.1-2 mm wide, solitary, appressed to the branch axes, elliptic-lanceolate, glabrous, light stramineous, apices acute to acuminate. Lower glumes absent (rarely present); upper glumes and lower lemmas glabrous, 3-veined; upper florets white. Caryopses 2.8-3.1 mm, yellow. 2n = 20, 40, 60.

Paspalum vaginatum grows in brackish and salt marshes. It is native to warm, coastal regions around the world, including the Americas. It has been grown for turf and in lawn trials, but is not yet widely used for these purposes.


9.   Paspalum almum Chase
Comb's Paspalum

Plants perennial; cespitose, shortly rhizomatous. Culms 10-50 cm, erect. Sheaths glabrous or sparsely pubescent; ligules 0.5-2 mm; blades to 20 cm long, 1.5-3.8 mm wide, flat, pubescent. Panicles terminal, usually composed of a digitate pair of branches, 1-5 additional branches sometimes present below; branches 1.8-7.1 cm, diverging to erect; branch axes 0.8-1.3 mm wide, winged, terminating in a spikelet. Spikelets 3-3.6 mm long, 1.3-1.8 mm wide, solitary (rarely paired), appressed to the branch axes, elliptic, glabrous, apices acute to acuminate. Lower glumes absent; upper glumes and lower lemmas glabrous, 5-veined, margins flat; upper florets stramineous to golden brown. 2n = 12, 24, 48 [J.H. Hunziker, F.O. Zuloaga, O. Morrone, and A. Escobar. 1998. Estudios cromosómicos en Paniceae sudamericanas (Poaceae: Panicoideae). Darwiniana 35:29-36].

Paspalum almum was probably introduced to North America as a forage species. Its native range is Brazil, Paraguay, Uruguay, and eastern Argentina. It has not been reported from Mexico or Central America. In the Flora region, it is found along roadsides and in pastures of southeastern Texas and southern Louisiana.


10.   Paspalum notatum Flüggé
Bahiagrass

Plants perennial; rhizomatous. Culms 20-110 cm, erect; nodes glabrous. Sheaths glabrous or pubescent; ligules 0.2-0.5 mm; blades 5-31 cm long, 2-10 mm wide, flat or conduplicate, glabrous or pubescent. Panicles terminal, usually composed of a digitate pair of branches, 1-3 additional branches sometimes present below the terminal pair; branches 3-15 cm, diverging to erect; branch axes 0.7-1.8 mm wide, narrowly winged, glabrous, margins scabrous, terminating in a spikelet, distal spikelets sometimes reduced. Spikelets 2.5-4 mm long, 2-2.8 mm wide, solitary, appressed to the branch axes, broadly elliptic to ovate or obovate, glabrous, light stramineous to white, apices obtuse to broadly acute. Lower glumes absent; upper glumes glabrous, 5-veined; lower lemmas 5-veined, margins inrolled; upper florets light yellow to white. Caryopses 2-3 mm, white. 2n = 20, 30, 40.

Paspalum notatum is native from Mexico through the Caribbean and Central America to Brazil and northern Argentina. It was introduced to the United States for forage, turf, and erosion control. It is now established, generally being found in disturbed areas and at the edges of forests in the southeastern United States.

Paspalum notatum is sometimes treated as having distinct varieties. They are not recognized here because the variation among them is continuous. A number of cultivars have been developed for use as turf grasses. Among these cultivars are 'Common Bahiagrass', 'Pensacola Bahiagrass', and 'Argentine Bahiagrass'.


11.   Paspalum minus E. Fourn.
Matted Paspalum

Plants perennial; shortly rhizomatous. Culms 3-60 cm, erect; nodes glabrous. Sheaths glabrous or pubescent; ligules 0.2-0.7 mm; blades 8-18 cm long, 2-7.1 mm wide, flat, glabrous or pubescent. Panicles terminal, usually composed of a digitate pair of branches, a third branch sometimes present below the terminal pair; branches 1.8-6.4 cm, diverging to erect; branch axes 0.5-1.3 mm wide, narrowly winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 1.9-2.3 mm long, 1.2-2 mm wide, solitary, appressed to the branch axes, broadly elliptic to ovate to obovate, glabrous, stramineous, apices obtuse. Lower glumes absent; upper glumes 3-veined, lower lemmas faintly 3-veined; upper florets stramineous. Caryopses 1.8-2.2 mm, white. 2n = 20, 40, 50.

Paspalum minus grows in disturbed areas and on the edges of forests. It grows from southern Texas to Florida in the Flora region; outside the region, it extends through Mexico and the West Indies to Peru, Bolivia, Brazil, and Paraguay.


12.   Paspalum blodgettii Chapm.
Coral Paspalum

Plants perennial; cespitose, bulbous; scales pubescent. Culms 40-100 cm, erect; nodes glabrous. Sheaths pubescent or glabrous; ligules 0.2-0.4 mm; blades 5-27 cm long, 1.9-8 mm wide, flat, glabrous, pubescent behind the ligules, margins scabrous, often ciliate basally. Panicles terminal, with 2-6 racemosely arranged branches; branches 1.5-7.5 cm, diverging to spreading; branch axes 0.5-0.8 mm wide, narrowly winged, terminating in a spikelet. Spikelets 1-1.3 mm long, 0.7-0.9 mm wide, paired, appressed to the branch axes, elliptic to elliptic-obovate, glandular pubescent, stramineous to light or golden brown. Lower glumes absent; upper glumes and lower lemmas 3-veined; upper florets 0.8-1.1 mm, stramineous. Caryopses 0.9-1.1 mm in diameter, orbicular, amber. 2n = 40.

Paspalum blodgettii grows in hammocks, low pinelands, and along roadsides in southern peninsular Florida, the Bahamas, the Greater Antilles, southeastern Mexico, and Belize.


13.   Paspalum paniculatum L.
Arrocillo

Plants perennial; cespitose or rhizomatous. Culms to 100 cm, erect; nodes pubescent. Sheaths pubescent; ligules 0.2-0.5 mm; blades 12-35 cm long, 10-24 mm wide, flat, scabrous, pubescent near the margins, margins usually undulate. Panicles terminal, with 18-50 racemosely arranged branches; branches 0.8-8.9 cm, spreading to diverging, often arcuate; branch axes 0.2-0.5 mm wide, narrowly winged, scabrous, terminating in a spikelet. Spikelets 1.1-1.3 mm long, 0.9-1 mm wide, paired, diverging from the branch axes, ovate, light brown to stramineous. Lower glumes absent; upper glumes and lower lemmas pubescent, 3-veined; upper florets 1.1-1.3 mm, stramineous. Caryopses 0.7-0.8 mm, light brown. 2n = 20, 40, 60.

Paspalum paniculatum is native from Mexico and the West Indies to Argentina. It is now established in Mississippi and southern Florida, growing in disturbed areas.


14.   Paspalum fimbriatum Kunth
Winged Paspalum, Panama Crowngrass

Plants annual. Culms 15-70 cm, erect; nodes glabrous or pubescent. Sheaths pubescent, sometimes sparsely so; ligules 1-1.9 mm; blades to 35 cm long, 1.9-16.2 mm wide, flat, sparsely pubescent on both surfaces, margins ciliate basally. Panicles terminal, with 2-8 racemosely arranged branches; branches 2-6.4 cm, diverging to erect; branch axes 0.9-1.6 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 2.5-3.5 mm long, 2.4-3 mm wide, paired, appressed to the branch axes, suborbicular, stramineous. Lower glumes absent; upper glumes and lower lemmas 1.9-2.1 mm, ovate, winged, 1-veined, margins ciliate-lacerate; upper florets 1.7-1.9 mm, stramineous. Caryopses 0.9-1.1 mm, orbicular, white. 2n = 20.

Paspalum fimbriatum has probably been introduced into the United States. Its primary range extends from southern Mexico to Colombia, Venezuela, and French Guiana. In the Flora region, it grows in disturbed areas of Florida.


15.   Paspalum dilatatum Poir.
Dallisgrass

Plants perennial; cespitose, rhizomatous, rhizomes short (less than 1 cm), forming a knotty base. Culms 50-175 cm, erect; nodes glabrous. Sheaths glabrous or pubescent, lower sheaths more frequently pubescent than the upper sheaths; ligules 1.5-3.8 mm; blades to 35 cm long, 2-16.5 mm wide, flat, mostly glabrous, adaxial surfaces with a few long hairs near the base. Panicles terminal, with 2-7 racemosely arranged branches; branches 1.5-12 cm, racemose, divergent; branch axes 0.7-1.4 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 2.3-4 mm long, 1.7-2.5 mm wide,paired, appressed to the branch axes, ovate, tapering to an acute apex, stramineous (rarely purple). Lower glumes absent; upper glumes and lower lemmas 5-7-veined, margins pilose; upper florets stramineous. Caryopses 2-2.3 mm, white to brown. 2n = 20, 40, 50-63.

Paspalum dilatatum is native to Brazil and Argentina. It is now well established in the Flora region, generally as a weed in waste places. It is also used as a turf grass.


16.   Paspalum urvillei Steud.
Vaseygrass

Plants perennial; cespitose, with a knotty base composed of very short (less than 1 cm) rhizomes. Culms 50-220 cm, erect; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1-4(7.7) mm; blades 12-60 cm long, 2-12 mm wide, flat, mostly glabrous, a few long hairs near the base of the adaxial surface. Panicles terminal, with (4)10-30 racemosely arranged branches; branches 1.2-11.5 cm, divergent; branch axes 0.5-1.1 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet. Spikelets 1.8-2.8 mm long, 1.1-1.5 mm wide, paired, appressed to the branch axes, elliptic to slightly obovate, stramineous (rarely purple). Lower glumes absent; upper glumes and lower lemmas 3-veined, margins pilose; upper florets stramineous. Caryopses 1.2-1.7 mm, white. 2n = 40.

Paspalum urvillei has been introduced to the United States from South America. In the Flora region it grows in disturbed, moist to wet areas, primarily in the southeastern United States.


17.   Paspalum modestum Mez
Water Paspalum

Plants perennial; usually sprawling , occasionally cespitose. Culms 30-110 cm, decumbent and rooting at the lower nodes; nodes glabrous. Sheaths glabrous; ligules 1-2.3 mm; blades to 50 cm long, 2-10 mm wide, flat, glabrous or pubescent. Panicles terminal, with 2-6(10) racemosely arranged branches; branches 3.5-12.5 cm, diverging to erect; branch axes 1-2.1 mm wide, glabrous, terminating in a spikelet. Spikelets 2.5-3 mm long, 1.3-1.6 mm wide, paired, appressed to the branch axes, elliptic, light brown. Lower glumes often present, 0.5-2 mm, brown; upper glumes glabrous, 5-veined, margins entire, lower lemmas glabrous, 5-7-veined, margins entire; upper florets olive, golden brown, or dark brown. Caryopses 1.6-1.8 mm, brown. 2n = 20, 30, 40.

Paspalum modestum grows in wet roadside ditches and rice fields of Texas and southern Louisiana. It was introduced to the United States from South America. Plants with pale florets may key to P. lividum, which differs from P. modestum in having shorter ligules.

Until recently, plants belonging to Paspalum modestum have been called P. hydrophilum Henrard in North America, but experimental studies have shown that the two species are quite distinct and that North American plants belong to P. modestum.


18.   Paspalum boscianum Flüggé
Bull Paspalum

Plants annual. Culms 15-96 cm, erect or prostrate, often rooting at the lower nodes; nodes glabrous. Sheaths glabrous; ligules 1-3.2 mm; blades to 56 cm long, 2.2-15 mm wide, flat. Panicles terminal, with 1-10(28) racemosely arranged branches; branches 1.2-8.2 cm, diverging; branch axes 0.7-2.3 mm wide, glabrous, broadly winged, wings about as wide as the central portion, margins scabrous, terminating in a spikelet. Spikelets 2-2.2 mm long, 1.3-1.8 mm wide, paired, appressed to the branch axes, glabrous, broadly elliptic, obovate, or orbicular, light to dark brown. Lower glumes absent; upper glumes glabrous, 5-veined, margins entire; lower lemmas glabrous, 3-5-veined, margins entire; upper florets dark glossy brown. Caryopses 1.4-1.6 mm, white. 2n = 40.

Paspalum boscianum grows in moist to dry, disturbed areas, and at the edges of forests. It is native from the southeastern United States through the West Indies and Mexico to Brazil. The California record came from a weed in a rice field.


19.   Paspalum virgatum L.
Talquezal

Plants perennial; cespitose. Culms 100-200 cm, stout, erect; nodes glabrous. Sheaths pubescent; ligules 1.9-2.2 mm, brown; blades 30-90 cm long, 1-3 cm wide, flat, glabrous, pubescent behind the ligules. Panicles terminal, with 10-20 racemosely arranged branches; branches 3-15 cm, spreading to diverging; branch axes 1-1.7 mm wide, winged, wings narrower than the central section, terminating in a spikelet. Spikelets 2.2-3.2 mm long, 1.8-2.4 mm wide, paired, appressed to or diverging from the branch axes, obovate, brown. Lower glumes absent; upper glumes and lower lemmas glabrous or variously short pubescent, 5-veined, margins entire; upper florets 2.5-2.7 mm, brown. 2n = 36, 40, 54, 80.

Paspalum virgatum is native from Mexico to South America. It has been introduced to the southeastern United States, where it grows primarily in disturbed areas and cultivated fields.


20.   Paspalum conspersum Schrad.
Scattered Paspalum

Plants perennial; cespitose. Culms 100-200 cm, stout, erect; nodes glabrous. Sheaths glabrous or sparsely pubescent; ligules 1-2 mm, brown; blades to 50 cm long, 7-18 mm wide, flat, glabrous or pubescent, margins scabrous, ciliate. Panicles terminal, with 4-13 racemosely arranged branches; branches 6-11 cm, diverging, divaricate, or reflexed; branch axes 0.5-1(1.2) mm wide, winged, wings narrower than the central section, terminating in a spikelet. Spikelets 2-2.7(3) mm long, 1.1-1.8 mm wide, paired, appressed to or diverging from the branch axes, elliptic to obovate, pubescent, brown. Lower glumes absent; upper glumes densely short pubescent, hairs about 0.5 mm; lower lemmas glabrous or sparsely short pubescent, margins entire; upper florets 1.8-2.2 mm, pubescent, brown. 2n = 40, 60.

Paspalum conspersum is native from Mexico to Argentina, but it has been introduced to the southern United States. It is grown for its forage value, and has become established at scattered locations from Texas to Florida, growing along roadsides and in other disturbed areas.


21.   Paspalum convexum Humb. & Bonpl. ex Flüggé
Mexican Paspalum

Plants annual. Culms 10-53 cm, erect; nodes glabrous. Sheaths pubescent or glabrous; ligules 2-4.1 mm; blades 5-25(80) cm long, 2.9-10.2(12) mm wide, flat. Panicles terminal, with 1-5 racemosely arranged branches; branches 1.1-5.4(7) cm, divergent; branch axes 0.8-1.3 mm wide, not or narrowly winged, glabrous, terminating in a spikelet. Spikelets 2.1-2.6 mm long, 1.7-2.4 mm wide, paired, appressed to the branch axes, broadly obovate to suborbicular, shortly pubescent, light to dark brown. Lower glumes absent; upper glumes and lower lemmas shortly pubescent, 5-7-veined, margins entire; lower paleas rarely present; upper florets dark glossy brown. Caryopses 1.3-1.5 mm, white. 2n = 30, 32, 40, 60.

Paspalum convexum grows in disturbed areas in the southern United States. It is native from Mexico and the Caribbean Islands to Brazil. It is not considered to have particularly high forage value.


22.   Paspalum plicatulum Michx.
Brownseed Paspalum

Plants perennial; shortly rhizomatous, often indistinctly so. Culms 30-110 cm, stout, erect; nodes glabrous. Sheaths glabrous; ligules 2-3 mm; blades to 35 cm long, 2-5.4 mm wide, conduplicate (rarely flat). Panicles terminal, with 2-7 racemosely arranged branches; branches 1.6-7.1 cm, usually divergent, rarely merely ascending; branch axes 0.6-1.1 mm wide, glabrous, terminating in a spikelet. Spikelets 2.5-3 mm long, 1.5-2.2 mm wide, paired, appressed to the branch axes, elliptic-ovate, light to dark brown. Lower glumes absent; upper glumes usually with short, appressed pubescence, rarely glabrous, 5-veined, margins entire; lower lemmas with short, appressed pubescence or glabrous, 3-veined, margins entire; upper florets dark glossy brown. Caryopses 1.4-1.6 mm, brown. 2n = 20, 40, 60.

Paspalum plicatulum grows in prairies, along forest margins, and in disturbed areas. Its range extends from the southeastern United States through the Caribbean and Mexico to Bolivia, Paraguay, and Argentina.


23.   Paspalum wrightii Hitchc. & Chase
Wright's Paspalum

Plants perennial; aquatic to semi-aquatic, conspicuously rhizomatous or stoloniferous. Culms 80-150 cm, erect; nodes glabrous. Sheaths glabrous or sparsely pubescent; ligules 1-3 mm; blades to 35 cm long, 2-7 mm wide, flat, glabrous above, pubescent below, especially basally. Panicles terminal, with 5-8 racemosely arranged branches; branches 3.5-11 cm, divergent to erect; branch axes 0.6-1.1 mm wide, glabrous, terminating in a spikelet. Spikelets 2.2-2.7 mm long, 1-1.4 mm wide, paired, appressed to or divergent from the branch axes, elliptic, glabrous, light brown. Lower glumes absent; upper glumes glabrous, 3-veined; lower lemmas glabrous, 5-veined; upper florets glossy chestnut brown. 2n = unknown.

The range of Paspalum wrightii extends from Cuba and Campeche, Mexico, to Bolivia, Paraguay, and Argentina. It is now established in the Flora region, growing along wet, roadside ditches, primarily along the Gulf coast of Texas.


24.   Paspalum nicorae Parodi
Brunswickgrass

Plants perennial; rhizomatous, rhizomes 5-25 cm, conspicuous. Culms 10-70 cm, erect to ascending; nodes glabrous. Sheaths glabrous, pubescent apically; ligules 1.2-1.5 mm; blades 6-20 cm long, 4-5 mm wide, flat to conduplicate, glabrous or pubescent. Panicles terminal, with 2-5 racemosely arranged branches; branches 1.4-5.2 cm, divergent; branch axes about 0.8 mm wide, glabrous, terminating in a spikelet. Spikelets 2.3-2.7 mm long, 1.4-1.8 mm wide, paired, appressed to or divergent from the branch axes, elliptic, dark brown. Lower glumes absent; upper glumes shortly pubescent, 5-veined, margins entire; lower lemmas transversely rugose at maturity, glabrous, 5-veined, margins entire; upper florets dark glossy brown. Caryopses about 1.8 mm long, 1.4 mm wide, ellipsoidal. 2n = 40.

Paspalum nicorae is native to Brazil, Uruguay, and Argentina. It was introduced to the United States for use in pastures and as a cover crop in waterways. It is now established in the southeastern United States, growing as a weed in pastures, turf, and other disturbed areas.


25.   Paspalum malacophyllum Trin.
Ribbed Paspalum

Plants perennial; cespitose, sometimes with short rhizomes. Culms 90-200 cm, erect; nodes sunken, glabrous or pubescent, brown. Sheaths pubescent; ligules 4-5 mm, membranous, brown, acute; blades 12-40 cm long, 8-35 mm wide, flat or conduplicate, pubescent below, glabrous above, distinctly pubescent basally. Panicles terminal, with 8-25 racemosely arranged branches; branches 1-8 cm, divergent to erect; branch axes 1-1.2 mm wide, margins scabrous, terminating in a spikelet; pedicels 0.2-0.4 and 0.5-1.2 mm long, flattened, scabrous. Spikelets 1.8-2 mm, paired, appressed to or divergent from the branch axes, oblong-elliptic, white to stramineous. Glumes absent; lower lemmas glabrous, ribbed over the veins, sulcate between, 5-veined, margins entire; upper lemmas as long as the lower ones, longitudinally papillose-striate, glabrous, pale-colored. Upper florets white to stramineous. 2n = 40, 60.

Paspalum malacophyllum is native from Mexico to Bolivia and Argentina. It was introduced to the southern United States for forage and soil conservation, and is now established in the southeastern United States, growing in disturbed sites at scattered locations.


26.   Paspalum racemosum Lam.
Peruvian Paspalum

Plants annual; cespitose or rhizomatous. Culms 40-90 cm, erect; nodes purple. Sheaths glabrous; ligules 0.1-0.3 mm; blades 4-13 cm long, 10-22 mm wide, flat, glabrous. Panicles terminal, with 40-75 racemosely arranged branches; branches 1-2.5 cm, divergent to erect; branch axes 1-1.5 mm wide, terminating in a pedicellate spikelet. Spikelets 2.5-2.9 mm long, 0.8-1.2 mm wide, paired, appressed to or divergent from the branch axes, linear-elliptic, pubescent, stramineous or purplish. Lower glumes absent; upper glumes and lower lemmas rugose, shortly ciliate; lower lemmas lacking ribs over the veins; upper florets 1.3-1.6 mm, stramineous, oblong elliptic, pale, shiny. Caryopses white. 2n = unknown.

Paspalum racemosum is native to Colombia, Ecuador, and Peru. Within the Flora region, it is known from disturbed sites at a few widely scattered locations.


27.   Paspalum intermedium Munro ex Morong & Britton
Intermediate Paspalum

Plants perennial; shortly rhizomatous. Culms to 200 cm, erect; nodes glabrous. Sheaths glabrous; ligules 2-3 mm; blades to 57 cm long, 2-3 cm wide, flat, glabrous below, appressed pubescent above. Panicles terminal, with 60-100 racemosely arranged branches; branches 1-13 cm, divergent to spreading, often arcuate; branch axes 0.9-1.2 mm wide, winged, margins scabrous, long pubescent. Spikelets 2-2.4 mm long, 0.9-1.2 mm wide, paired, divergent to spreading from the branch axes, elliptic to ovate, glabrous or pubescent, stramineous, sometimes partially purple. Lower glumes absent; upper glumes smooth, 3-veined, margins entire, sparsely short-pubescent, at least distally; lower lemmas smooth, lacking ribs over the veins, 3-veined, margins entire, glabrous or shortly pubescent; upper florets stramineous to white. Caryopses 1.5-1.7 mm, golden brown. 2n = 20, 40.

Paspalum intermedium is an introduced roadside weed in the Flora region. It is found in Mexico and South America, but not in Central America (Pohl and Davidse 1994).


28.   Paspalum coryphaeum Trin.
Emperor Paspalum

Plants perennial; cespitose, not rhizomatous. Culms 65-400 cm, erect; nodes pilose. Sheaths papillose-hirsute (upper sheaths sometimes glabrous); ligules 1-4.5 mm; blades 30-50 cm long, 10-23 mm wide, flat, with long hairs behind the ligules, otherwise glabrous or puberulent adaxially. Panicles terminal, with (6)15-44 racemosely arranged branches; branches 5-13 cm, straight, spreading to reflexed, rarely merely divergent; branch axes 0.3-0.4 mm wide, narrowly winged, glabrous, margins scabrous, pubescent, terminating in a spikelet. Spikelets 2-2.5 mm long, 1.8-1.9 mm wide, paired, divergent to spreading from the branch axes, elliptic, brown to stramineous, often purple-tinged. Lower glumes usually absent, if present, to 0.9 mm, triangular; upper glumes smooth, papillose-hirsute, 3-veined; lower lemmas smooth, papillose-hirsute or glabrous, 3-veined; upper florets white. 2n = 20, 40, 60.

Paspalum coryphaeum is native from Costa Rica and the Caribbean south to northern South America. In the Flora region, it grows in disturbed habitats at scattered southeastern locations.


29.   Paspalum quadrifarium Lam.
Paja Manse, Paja Colorada, Tussock Paspalum

Plants perennial; cespitose. Culms (50)100-180 cm, erect; nodes pubescent. Sheaths pubescent, margins extending into auricles; ligules 1-6.3 mm; blades 15-62 cm long, 4.9-6.1 mm wide, involute to flat, glabrous. Panicles terminal, with 15-44 racemosely arranged branches; branches 1.2-8.5 cm, straight, erect to ascending, lower branches longer than those above; branch axes 0.5-0.6 mm wide, narrowly winged, glabrous, margins scabrous, pubescent, terminating in a spikelet. Spikelets 2-2.5(3) mm long, 0.9-1.3 mm wide, paired, divergent to spreading from the branch axes, elliptic, brown to stramineous, often purple-tinged. Lower glumes usually absent, if present, to 0.9 mm, triangular; upper glumes shortly pubescent, 3-veined, purple-spotted, margins entire; lower lemmas glabrous or pubescent, lacking ribs over the veins, 3-veined, margins entire; upper florets 2.2-2.5 mm, white. 2n = 20, 30, 40.

Paspalum quadrifarium is native to Uruguay, Paraguay, Brazil, and Argentina. It is grown as an ornamental in Florida, but has also become established in disturbed habitats of the southeastern United States. It is considered a noxious weed in New South Wales, Australia.


30.   Paspalum bifidum (Bertol.) Nash
Pitchfork Paspalum

Plants perennial; rhizomatous. Culms 60-140 cm, erect; nodes glabrous.Sheaths pubescent; ligules 2-4 mm; blades to 37 cm long, 2.2-11 mm wide, flat. Panicles terminal, with 2-5 racemosely arranged branches; branches 3.7-13 cm, divergent to erect; branch axes 0.2-0.8 mm wide, glabrous, margins scabrous, terminating in a spikelet. Spikelets 3.1-4 mm long, 2-2.5 mm wide, paired, not imbricate, appressed to the branch axes, elliptic to obovate, yellow-brown. Lower glumes present or absent; upper glumes glabrous or sparsely pubescent basally, (6)7-veined, margins entire; lower lemmas glabrous or sparsely pubescent basally, lacking ribs over the veins, 5-veined, margins entire; upper florets white. Caryopses 2.6-2.9 mm, purple. 2n = unknown.

Paspalum bifidum is restricted to the southeastern United States. It grows at the edges of forests in longleaf pine-oak-grass ecosystems, usually in dry to mesic loamy sandy soils. It grows vigorously following fire.


31.   Paspalum langei (E. Fourn.) Nash
Rustyseed Paspalum

Plants perennial; cespitose. Culms 23-125 cm, erect; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 0.6-1.9 mm; blades to 38 cm long, 4-18 mm wide, flat, glabrous or pubescent, dark green. Panicles terminal, with 1-3(4) racemosely arranged branches; branches 2.3-13.4 cm, erect to divergent, terminating in a spikelet; branch axes 0.2-1 mm wide, glabrous, margins scabrous. Spikelets 2.1-3.3 mm long, 1.3-1.6 mm wide, paired, imbricate, appressed to the branch axes, elliptic to obovate, stramineous to brown. Lower glumes 0.4-1.2(1.8) mm, stramineous to brown; upper glumes with papillose-based short pubescence, 3- or 5-veined, margins entire, lower lemmas with papillose-based short pubescence, lacking ribs over the veins, 3-veined, margins entire; upper florets light stramineous. Caryopses 1.3-1.5 mm, light to dark brown. 2n = 40, 60.

Paspalum langei is native from Texas to Florida, and extends through Mexico to Venezuela and the Antilles. It grows at the edges of moist woods and in disturbed areas.


32.   Paspalum setaceum Michx.

Plants perennial; cespitose or shortly rhizomatous. Culms 25-110 cm, erect, spreading, or prostrate; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 0.2-0.5 mm; blades flat, glabrous or pubescent. Panicles terminal and axillary, with 1-6 racemosely arranged branches, axillary panicles partially or completely enclosed by the subtending leaf sheath; branches 2-12(17) cm, ascending to spreading, often arcuate, terminating in a spikelet; branch axes 0.2-1.2 mm wide, glabrous, sometimes scabrous. Spikelets 1.4-2.6 mm long, paired, imbricate, appressed to the branch axes, elliptic to obovate to ovate to orbicular, stramineous or brown. Lower glumes absent; upper glumes and lower lemmas glabrous or shortly glandular-pubescent, 3-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets stramineous. Caryopses elliptic to suborbicular, white. 2n = 20.

Paspalum setaceum is a variable species that grows east of the Rocky Mountains in the contiguous United States and Mexico. The following treatment summarizes the major patterns of variation within the species. Some specimens will be hard to place, particularly old herbarium specimens that have lost their color. Nine varieties grow in the Flora region.

1
Leaf blades conspicuously basal, recurved, 3-10 mm wide; lower lemmas without evident midveins (2)
Leaf blades more evenly distributed, lax to straight, 1.5-20 mm wide; lower lemmas with or without evident midveins (3)
2
Leaf blades yellowish-green, usually glabrous; spikelets usually glabrous, not spotted ..... var. longepedunculatum
Leaf blades grayish-green, hirsute; spikelets short pubescent, often spotted ..... var. villosissimum
3
Leaf blades glabrous (or almost so) on the surfaces, sometimes ciliate on the margins (4)
Leaf blades evidently hirsute on the surfaces as well as on the margins (6)
4
Leaf blades 2.4-6.1 mm wide, stiff; spikelets 2-2.6 mm long ..... var. rigidifolium
Leaf blades 3-18 mm wide, lax to somewhat stiff but, if somewhat stiff, more than 6 mm wide; spikelets 1.7-2.4 mm long (5)
5
Lower lemmas without evident midveins; blades yellowish-green to dark green ..... var. stramineum
Lower lemmas with evident midveins; blades dark green to purplish ..... var. ciliatifolium
6
Plants widely spreading to prostrate (7)
Plants erect to spreading (8)
7
Leaf blades grayish-green; lower lemmas without evident midveins ..... var. psammophilum
Leaf blades yellowish-green; lower lemmas with or without evident midveins ..... var. supinum
8
Lower lemmas usually with evident midveins; spikelets 1.8-2.5 mm long, usually glabrous, light green to green ..... var. muhlenbergii
Lower lemmas usually without evident midveins; spikelets 1.4-2.4 mm long, usually pubescent, pale yellow to light green (9)
9
Leaves grayish-green; blades 1.5-7 mm wide, always conspicuously hirsute ..... var. setaceum
Leaves yellowish-green to dark green; blades 3.3-13.5 mm wide, almost glabrous or conspicuously hirsute ..... var. stramineum


Paspalum setaceum var. ciliatifolium (Michx.) Vasey
Fringeleaf Paspalum

Plants erect to spreading. Leaves mostly cauline; blades 2-32 cm long, 3-18 mm wide, lax to somewhat stiff, glabrous or with a few hairs along the midrib (rarely shortly pilose), dark green to purple, margins scabrous, ciliate. Panicle branches 2-11.9 cm; branch axes 0.6-1.2 mm wide. Spikelets 1.7-2 mm long, 1.2-1.5 mm wide, elliptic to obovate, pubescent or occasionally glabrous; lower lemmas with an evident midvein; upper florets 1.7-2 mm.

Paspalum setaceum var. ciliatifolium is the most variable and widespread of the nine varieties of P. setaceum. It usually grows in sandy soil in open areas, including disturbed areas, of prairies and forest margins. Its range extends from Louisiana and the eastern United States to Panama, the West Indies, and Bermuda.


Paspalum setaceum var. longepedunculatum (Leconte) Alph. Wood
Barestem Paspalum

Plants erect. Leaves mostly basal; blades to 15 cm long, 3-10 mm wide, glabrous, usually recurved, yellow-green, margins ciliate. Panicle branches 2.4-9.2 cm long, ascending or nodding, arcuate; branch axes 0.2-0.6 mm wide. Spikelets 1.4-1.8 mm long, 0.9-1.3 mm wide, elliptic to obovate or suborbicular, glabrous or with scattered glandular hairs, not spotted; lower lemmas without an evident midvein; upper florets 1.4-1.8 mm.

Paspalum setaceum var. longepedunculatum grows on open ground, usually in moist areas such as along ditches and roadsides, as well as in flatwoods. It is found primarily in the coastal plain of the southeastern United States, but has also been found in Ohio, Kentucky, and Tennessee. It is similar to var. villosissimum, differing in its glabrous leaves, more delicate habit, and more poorly-developed rhizomes. Both varieties grow in peninsular Florida, but var. longepedunculatum also grows along the coast as far west as the Mississippi delta and as far north as southern North Carolina.


Paspalum setaceum var. muhlenbergii (Nash) D.J. Banks
Hurrahgrass

Plants mostly erect. Leaves mostly cauline; blades to 25 cm long, 2-10.2 mm wide, lax to straight, surfaces and margins evenly hirsute, hairs 1.5-5.5 mm, light to dark green. Panicle branches 1.9-14.3 cm; branch axes 0.5-1 mm wide. Spikelets 1.8-2.5 mm long, 1.5-2 mm wide, oval to suborbicular, glabrous or with a few hairs, light green to green; lower lemmas usually with an evident midvein; upper florets 1.8-2.3 mm.

Paspalum setaceum var. muhlenbergii is endemic to the Flora region, extending from southern Ontario to the Gulf coast of Texas and northern Florida. It grows in disturbed areas and on the margins of forests. It resembles var. supinum, differing in its erect habit and, usually, in its spikelet shape and presence of a midvein on the lower lemma.


Paspalum setaceum var. psammophilum (Nash) D.J. Banks
Sand Paspalum

Plants spreading to prostrate. Leaves mostly cauline; blades to 16 cm long, 2.8-8.3 mm wide, lax to straight, grayish-green, surfaces and margins evidently hirsute, with soft, short hairs. Panicle branches 3.1-5.9 cm; branch axes 0.7-1 mm wide. Spikelets 1.8-2.2 mm long, 1.6-1.8 mm wide, suborbicular to orbicular, pubescent; lower lemmas without an evident midvein; upper florets 1.8-2.1 mm.

Paspalum setaceum var. psammophilum grows in sandy, maritime habitats and, inland, along sandy roadsides and in dry fields, from Massachusetts to the District of Columbia. The combination of its spreading to prostrate habit and densely puberulent foliage distinguishes it from other varieties of P. setaceum.


Paspalum setaceum var. rigidifolium (Nash) D.J. Banks
Stiff Paspalum

Plants erect to spreading. Leaves mostly cauline; blades to 30 cm long, 2.4-6.1 mm wide, conspicuously rigid, stiff, pubescent adaxially, glabrous or sparsely pubescent abaxially, margins sometimes ciliate. Panicle branches 4.8-11.3 cm; branch axes 0.7-1.1 mm wide. Spikelets 2-2.6 mm long, 1.6-1.8 mm wide, obovate to ovate, pubescent, sometimes sparsely so; lower lemmas with or without an evident midvein; upper florets 2-2.4 mm.

Paspalum setaceum var. rigidifolium grows on hammocks, sand barrens, high pinelands, and flatwoods of Georgia, Florida, and Cuba.


Paspalum setaceum Michx. var. setaceum
Thin Paspalum

Plants erect. Leaves mostly cauline; blades to 22 cm long, 1.5-7 mm wide, lax to straight, conspicuously hirsute, usually with long stiff hairs and short soft hairs, grayish-green, margins hirsute. Panicle branches 2-11.2 cm; branch axes 0.3-0.9 mm wide. Spikelets 1.4-1.9 mm long, 1.1-1.6 mm wide, elliptic, obovate, orbicular, or suborbicular, pubescent to nearly glabrous; lower lemmas without an evident midvein; upper lemmas 1.3-2 mm.

Paspalum setaceum var. setaceum grows in open areas and sandy soils, often at the edges of forests, primarily on the southeastern coastal plain of the United States, from southern New England to eastern Mexico, but extending inland to western Virginia, Missouri, and Arkansas. It also grows in Cuba.


Paspalum setaceum var. stramineum (Nash) D.J. Banks
Yellow Sand Paspalum

Plants erect to spreading. Leaves mostly cauline; blades to 30 cm long, 3.3-13.5 mm wide, lax to somewhat stiff, glabrous or with a few hairs along the midrib, sometimes pubescent, yellow-green to dark green, margins scabrous, ciliate. Panicle branches 4-12 cm; branch axes 0.6-1.1 mm wide. Spikelets 1.7-2.4 mm long, 1.5-2.1 mm wide, obovate to suborbicular, pubescent or occasionally glabrous; lower lemmas without an evident midvein; upper florets 1.7-2.1 mm.

Paspalum setaceum var. stramineum grows at the edges of forests and in disturbed areas with sandy soil. Its range extends from the central plains and eastern United States to Mexico, Bermuda, and the West Indies.


Paspalum setaceum var. supinum (Bosc ex Poir.) Trin.
Supine Thin Paspalum, Thin Paspalum

Plants usually spreading. Leaves mostly cauline; bladesto 31 cm long, 2.2-19 mm wide, lax to straight, long pubescent, hairs 1.5-4 mm, yellow-green, margins ciliate, with long stiff hairs. Panicle branches 2.2-9.9 cm; branch axes 0.6-1.5 mm wide. Spikelets 1.7-2.1 mm long, 1.2-1.6 mm wide, elliptic to obovate (rarely suborbicular), glabrous or pubescent; lower lemmas with or without an evident midvein; upper florets 1.7-2.1 mm.

Paspalum setaceum var. supinum grows at the edges of forests and in disturbed areas. Within the Flora region, its range extends from Texas, Arkansas, and Louisiana to South Carolina, Georgia, and Florida.

Paspalum setaceum var. supinum resembles var. muhlenbergii, differing in its spreading habit and, usually, in its spikelet shape and lack of a midvein on the lower lemma.


Paspalum setaceum var. villosissimum (Nash) D.J. Banks
Hairy Paspalum

Plants erect. Leaves conspicuously basal; blades to 15 cm long, 3-10 mm wide, recurved, hirsute, usually with long stiff hairs and short soft hairs, grayish-green, margins ciliate, with long stiff hairs. Panicle branches 2-11.2 cm; branch axes 0.3-0.9 mm wide. Spikelets 1.4-1.9 mm long, 1.1-1.6 mm wide, elliptic, obovate, orbicular, or suborbicular, short pubescent to nearly glabrous, often purple-spotted; lower lemmas without an evident midvein; upper lemmas 1.3-2 mm.

Paspalum setaceum var. villosissimum grows in sandy fields and flatwoods of Florida and Cuba. It resembles var. longepedunculatum, differing in its pubescent leaves, more robust habit, and more developed rhizomes.


33.   Paspalum laxum Lam.
Coconut Paspalum

Plants perennial; cespitose to short rhizomatous. Culms 80-110 cm, erect; nodes glabrous. Sheaths glabrous, sparsely pubescent apically; ligules 1-2.9 mm; blades 9-41 cm long, 3-7 mm wide, mostly involute, pubescent above, glabrous below. Panicles terminal, with 1-5(10) racemosely arranged branches; branches 1.9-11.4 cm, erect to divergent, terminating in a spikelet; branch axes 0.4-0.7 mm wide, very narrowly winged, scabrous. Spikelets 1.6-2.2 mm long, 1.1-1.3 mm wide, paired, imbricate, appressed to the branch axes, elliptic-obovate to ovate. Lower glumes absent; upper glumes shortly pubescent, 5-veined, margins entire; lower lemmas glabrous or shortly pubescent, lacking ribs over the veins, 3-veined, margins entire; upper florets 1.4-2 mm, white to stramineous. 2n = 60.

Paspalum laxum grows in hammocks and along roads, often in sandy or limestone soils. It used to be common in coconut groves, hence the English-language name. It grows in southern Florida, the Antilles, and Belize.


34.   Paspalum caespitosum Flüggé
Blue Paspalum

Plants perennial; cespitose. Culms 20-60 cm, erect, base swollen, bulblike; cataphylls pubescent; nodes sparsely pubescent or glabrous. Sheaths pubescent or glabrous; ligules 0.2-0.4 mm; blades to 25 cm long, 1.9-6.2 mm wide, flat, glabrous, pubescent behind the ligules, margins scabrous, often ciliate basally. Panicles terminal, with 2-5(8) racemosely arranged branches; branches 0.9-4.4 cm, divergent to spreading, terminating in a spikelet; branch axes 0.2-0.5 mm wide, narrowly winged. Spikelets 1.3-2 mm long, 0.7-1 mm wide, paired (rarely appearing solitary as a result of aborted spikelets), imbricate, appressed to the branch axes, elliptic. Lower glumes absent; upper glumes and lower lemmas glabrous or sparsely and shortly pubescent basally or around the margins, 5-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets 1.3-1.8 mm, stramineous to golden brown. Caryopses 1.2-1.4 mm, ellipsoid, amber. 2n = 40.

Paspalum caespitosum grows in hammocks and sandy pinelands. It is native in southern Alabama, Florida, the West Indies, Mexico, and Central America.


35.   Paspalum virletii E. Fourn.
Virlet's Paspalum

Plants perennial; cespitose. Culms 40-75 cm, erect, not swollen at the base; nodes pubescent. Sheaths pubescent; blades to 15 cm long, 5-10 mm wide, flat, pubescent. Panicles terminal, with 3-8 racemosely arranged branches; branches 2-7 cm, spreading, terminating in a spikelet; branch axes narrow, sparsely pubescent. Spikelets 2-2.5 mm long, 1.4-1.6 mm wide, paired, imbricate, appressed to the branch axes, ovate. Lower glumes absent; upper glumes shortly pubescent, 3-veined, margins entire; lower lemmas glabrous, lacking ribs over the veins, 3-veined, margins entire; upper florets pale to stramineous or golden brown. 2n = unknown.

Paspalum virletii grows in dry, sandy soils in disturbed habits. It is known only from Arizona, where it is considered a rare species, and from Mexico, where it also appears to be either rare or poorly collected (COTECOCA 2000).


36.   Paspalum monostachyum Vasey
Gulfdune Paspalum

Plants perennial; rhizomatous. Culms 60-120 cm, erect; nodes glabrous. Sheaths glabrous; ligules 0.5-3 mm; blades to 50 cm long, 0.2-2(8) mm wide, involute (rarely flat), glabrous, pubescent behind the ligules. Panicles terminal, with 1-3 racemosely arranged branches; branches 5.6-23.3 cm, erect (rarely divergent), terminating in a spikelet; branch axes 0.5-1.2 mm wide, glabrous, margins scabrous to pubescent. Spikelets 2.3-3.7 mm long, 1.3-1.9 mm wide, paired, imbricate, appressed to the branch axes, elliptic to narrowly ovate, glabrous, stramineous (rarely partially purple). Lower glumes usually absent; upper glumes glabrous, 1-veined, margins entire; lower lemmas glabrous, lacking ribs over the veins, 3-veined, margins entire; upper florets stramineous. Caryopses 2-2.4 mm, yellow to golden brown. 2n = unknown.

Paspalum monostachyum grows in sand and muck soils on coastal sand dunes, wet prairie, marshes, and disturbed habitats of the southern coastal plain from Florida to eastern Mexico.


37.   Paspalum pleostachyum Döll
Tropical Paspalum

Plants perennial; cespitose. Culms 80-110 cm, erect; nodes glabrous. Sheaths glabrous, sparsely pubescent apically; ligules 1-2.9 mm; blades to 62 cm long, 3-7 mm wide, mostly involute, pubescent above, glabrous below. Panicles terminal, with 3-15 racemosely arranged branches; branches 5.2-12.5 cm, divergent to spreading, terminating in a spikelet; branch axes 0.3-0.8 mm wide, very narrowly winged, scabrous. Spikelets 2.2-2.5 mm long, 1-1.3 mm wide, paired, appressed to the branch axes, elliptic to obovate, white to light stramineous. Lower glumes absent; upper glumes glabrous, 5-veined; lower lemmas glabrous, 3-veined; upper florets 1.4-2 mm, white to stramineous. Caryopses 1-1.6 mm, suborbicular, brown. 2n = unknown.

Paspalum pleostachyum grows in sandy soil or rocky areas in Florida, the West Indies, and from northern South America to Brazil. It is usually found along the coast.


38.   Paspalum lividum Trin. ex Schltdl.
Longtom

Plants perennial; decumbent or cespitose. Culms 30-97 cm, erect; nodes glabrous. Sheaths glabrous or pubescent; ligules 2.2-4.7 mm; blades to 38 cm long, 2.3-6.2 mm wide, flat, glabrous or pubescent. Panicles terminal, with 3-11 racemosely arranged branches; branches 1.5-4 cm, divergent, occasionally arcuate, terminating in a spikelet; branch axes 1.5-2 mm wide, broadly winged, glabrous or sparsely pubescent, margins scabrous, usually slightly conduplicate, occasionally purple. Spikelets 2.2-2.6 mm long, 1.2-1.5 mm wide, paired, imbricate, appressed to divergent from the branch axes, elliptic to obovate, stramineous (rarely purple-spotted), margins scabrous apically. Lower glumes absent; upper glumes and lower lemmas glabrous, 5-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets white to pale. Caryopses 2-2.2 mm, brown. 2n = 40, 60.

Paspalum lividum grows in fresh and brackish marshes and ditches. It is native from the Gulf coast of the United States southward through Mexico and Central America to Cuba and Argentina. Plants of P. modestum with pale upper florets may be mistaken for P. lividum, but will have ligules that are only 1-2.3 mm long.

Zuloaga and Morrone regard Paspalum lividum as a synonym of P. denticulatum Trin. (http://mobot.mobot.org/W3T/Search/nwgc.html, viewed December 9, 2002).


39.   Paspalum praecox Walter
Early Paspalum

Plants perennial; shortly rhizomatous. Culms 5-160 cm, erect, not rooting at the lower nodes; nodes glabrous. Sheaths densely pubescent, occasionally glabrous; ligules 1-2.2 mm; blades to 55 cm long, 2.2-8.3 mm wide, conduplicate (occasionally flat), glabrous below, pubescent above. Panicles terminal, with 2-10 racemosely arranged branches; branches 0.8-10.3 cm, divergent to spreading, often arcuate, terminating in a spikelet; branch axes 0.8-2 mm wide, narrowly winged, glabrous, margins scabrous. Spikelets 2.1-3.1 mm long, 2-2.8 mm wide, paired, imbricate, appressed to divergent from the branch axes, orbicular to suborbicular, stramineous. Lower glumes absent; upper glumes and lower lemmas glabrous, 3-veined, margins entire; upper florets white to light yellow. Caryopses 1.9-2.1 mm, brown. 2n = 20, 40.

Paspalum praecox grows in pitcher plant bogs, wet pine flatwoods, wet savannahs, prairies, and wet streamhead ecotones. It is restricted to the United States, growing predominantly on the southeastern coastal plain.


40.   Paspalum hartwegianum E. Fourn.
Hartweg's Paspalum

Plants perennial; decumbent or cespitose. Culms 50-120 cm, erect; nodes glabrous. Sheaths glabrous, sparsely pubescent apically; ligules 2-5 mm; blades to 21 cm long, 2-5 mm wide, flat, glabrous, pubescent behind the ligules, margins ciliate basally. Panicles terminal, with 4-9 racemosely arranged branches; branches 2-6.5 cm, divergent to erect, terminating in a spikelet; branch axes 1.2-1.5 mm wide, winged, glabrous, margins scabrous. Spikelets 2.8-3 mm long, 1.5-1.6 mm wide, paired, imbricate, appressed to divergent from the branch axes, elliptic, stramineous. Lower glumes absent; upper glumes and lower lemmas abundantly pubescent, hairs longer than 0.1 mm, 3-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets 2.5-2.7 mm, white to stramineous. 2n = 60.

Paspalum hartwegianum grows in wet prairies, ditches, and swales from southern Texas through Mexico and Central America to Paraguay and Argentina.


41.   Paspalum pubiflorum Rupr. ex E. Fourn.
Hairyseed Paspalum

Plants perennial; usually decumbent, rooting at the nodes. Culms 30-130 cm, decumbent; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1-3.2 mm; blades to 31 cm long, 4-18 mm wide, flat, glabrous, with a few hairs behind the ligules. Panicles terminal, with 2-7 racemosely arranged branches; branches 2.2-7.9 cm, divergent to spreading, terminating in a spikelet; branch axes 1.1-2.3 mm wide, narrowly winged, glabrous, margins scabrous. Spikelets 2.8-3.6 mm long, 1.5-2 mm wide, paired, imbricate, appressed to divergent from the branch axes, elliptic to obovate, pubescent or glabrous, light brown to stramineous. Lower glumes absent; upper glumes and lower lemmas glabrous or sparsely pubescent, hairs shorter than 0.1 mm, 3-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets stramineous. Caryopses 1.8-2 mm, golden brown or white. 2n = 60, ca. 64.

Paspalum pubiflorum grows on the edges of forests and in disturbed areas. It is native to the southeastern United States, Mexico, and Cuba.


42.   Paspalum floridanum Michx.
Florida Paspalum

Plants perennial; rhizomatous. Culms 80-210 cm, erect; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1.2-3.3 mm; blades to 52 cm long, 3-18 mm wide, flat, glabrous or pubescent, usually densely pubescent behind the ligules. Panicles terminal, with 1-6 racemosely arranged branches; branches 3-17.9 cm, divergent to erect, terminating in a spikelet; branch axes 0.3-1.8 mm wide, glabrous, the margins scabrous. Spikelets 2.9-4.1 mm long, 1.9-3.1 mm wide, paired, imbricate, appressed to the branch axes, elliptic to suborbicular to orbicular, glabrous, stramineous. Lower glumes absent; upper glumes glabrous, 5-veined, margins entire; lower lemmas glabrous, lacking ribs over the veins, 3-veined, margins entire; upper florets golden brown. Caryopses 2.8 mm, amber. 2n = 120, 140, ca. 160-170.

Paspalum floridanum grows along the edges of forests, flatwoods, and pinewoods and in open areas. It is a frequent component of dry-mesic soils in longleaf pine-oak-grass ecosystems, and is restricted to the eastern United States.


43.   Paspalum unispicatum (Scribn. & Merr.) Nash
One-Spike Paspalum

Plants perennial; rhizomatous, not rooting at the lower nodes. Culms 50-80 cm, erect. Sheaths glabrous, pubescent apically, margins scarious; ligules 1-2 mm, membranous, lacerate; blades 3-4 mm wide, flat, glabrous, pubescent behind the ligules, margins papillose-ciliate. Inflorescence terminal, erect, a spicate raceme 7-15 cm long, or a panicle with 1-2 subterminal spicate branches that are wholly or partially enclosed in the upper sheath, often arcuate; branches terminating in a spikelet. Spikelets 2.7-3 mm, paired, imbricate, obovate, stramineous. Lower glumes absent, or 1-2.3 mm; upper glumes and lower lemmas glabrous, 3-veined, margins entire; lower lemma lacking ribs over the veins; lower florets often staminate; lower paleas 2.5-2.9 mm, membranous; upper florets 2.3-2.9 mm, white, stramineous, or golden brown. 2n = 40.

Paspalum unispicatum grows in sandy soil in the coastal plain of Texas and extends southward through Mexico and Central America to Cuba and Paraguay, Uruguay, and Argentina. It has not been reported from Brazil.