14.31 PHLEUM L.
Mary E. Barkworth
Plants annual or perennial; cespitose, sometimes rhizomatous, occasionally stoloniferous. Culms 2–150 cm, erect or decumbent; nodes glabrous. Sheaths open; auricles absent or inconspicuous; ligules membranous, not ciliate; blades usually flat. Inflorescences dense, spikelike panicles, more than 1 spikelet associated with each node; branches often shorter than 2 mm, always shorter than 7 mm, stiff; pedicels shorter than 1 mm, sometimes fused; disarticulation above the glumes or, late in the season, beneath the glumes. Spikelets strongly laterally compressed, bases usually U-shaped, sometimes cuneate, with 1 floret; rachillas glabrous, sometimes prolonged beyond the base of the floret. Glumes equal, longer and firmer than the florets, stiff, bases not connate, strongly keeled, keels usually strongly ciliate, sometimes glabrous, sometimes scabrous, 3-veined, apices truncate to tapered, midveins often extending into short, stiff, awnlike apices; calluses blunt, glabrous; lemmas white, often translucent, not keeled, 5–7-veined, unawned, bases not connate, apices acute, entire, sometimes with a weak, subapical awn; paleas subequal to the lemmas, 2-veined; lodicules 2, free, glabrous, toothed; anthers 3; ovaries glabrous. Caryopses elongate-ovoid; embryos 1/6–1/4 the length of the caryopses. x = 7. Name from the Greek phleos, the name of a reedy grass.
Phleum is a genus of approximately 15 species, most of which are native to Eurasia. One species, P. alpinum, is native to the Flora region and six are introduced. One of the introduced species, P. pratense, has been established in the region for a long time. It is widely cultivated as a fodder grass, both in the Flora region and in other parts of the world. Phleum phleoides was first recognized as being present in the Flora region in 1990. Phleum exaratum has been reported from the United States. No specimens supporting the report have been seen. It resembles P. arenarium but has anthers 1.5–2 mm long, rather than 0.3–1.2 mm long, and an inflorescence that is rounded at the base.
Species of Phleum are sometimes mistaken for Alopecurus, but Alopecurus has obtuse to acute glumes that are unawned or taper into an awn, lemmas that are both awned and keeled, and paleas that are absent or greatly reduced. The species of Phleum that are most abundant in the Flora region are easily recognized by their strongly ciliate, abruptly truncate, awned glumes and adnate panicle branches. In addition, in Phleum the lemmas are not keeled and the paleas are always subequal to the lemmas.
SELECTED REFERENCES Humphries, C.J. 1978. Notes on the genus Phleum. Bot. J. Linn. Soc. 76:337–340; Kula, A., B. Dudziak, E. Sliwinska, A. Grabowska-Joachimiak, A. Stewart, H. Golczyk, and A.J. Joachimiak. 2006. Cytomorphological studies on American and European Phleum commutatum Gaud. (Poaceae). Acta Biol. Cracov., Ser. Bot. 48:99–108.
For an interactive dichotomous key, click here; for an interactive, multientry key, click here.
1. Plants perennial ... 2.
1. Plants annual ... 4
2. Panicles tapering distally; panicle branches free from the rachis; glumes scabrous to shortly ciliate on the keels; plants known, in the Flora region, only from British Columbia ... P. phleoides
2. Panicles not tapering distally; panicle branches adnate to the rachises; glumes conspicuously ciliate on the keels; plants widespread in the Flora region ... 3
3. Sheaths of the flag leaves not inflated; panicles 2–14(17) cm long, 5–20 times as long as wide; lower internodes of the culms frequently enlarged or bulbous; widespread in the Flora region ... P. pratense
3. Sheaths of the flag leaves inflated; panicles 1–6 cm long, usually 1.5–3 times as long as wide; lower internodes of the culms not enlarged or bulbous ... P. alpinum
4. Glume apices abruptly truncate ... P. paniculatum
4. Glume apices gradually narrowed to tapered ... 5
5. Glumes semi-elliptical in outline, apices pointing towards each other; keels usually glabrous, sometimes scabrous ... P. subulatum
5. Glumes oblong-lanceolate, apices parallel or divergent; keels ciliate ... P. arenarium
1. Phleum pratense L.
Timothy, Fléole des Prés, Phléole des Prés, Mil
Plants perennial; loosely to densely cespitose. Culms (20) 50–150 cm, usually erect, lower internodes frequently enlarged or bulbous. Sheaths of the flag leaves not inflated; auricles occasionally present, incon-spicuous; ligules 2–4 mm, obtuse to acute; blades to 45 cm long, 4–8(10) mm wide, flat. Panicles (3)5–10(16) cm long, 5–7.5(10) mm wide, 5–20 times as long as wide, not tapering distally; branches adnate to the rachises. Glumes 3–4 mm, sides usually puberulent, keels pectinate-ciliate, apices awned, awns 1–1.5(2) mm; lemmas (1.2)1.7–2 mm, about 1/2 as long as the glumes, usually puberulent; anthers 1.6–2.3 mm. 2n = 42 (21, 35, 36, 49, 56, 63, 70, 84).
Phleum pratense grows in pastures, rangelands, and disturbed sites throughout most of the mesic, cooler regions of North America. Originally introduced from Eurasia as a pasture grass, it is now well established in many parts of the world, including the Flora region. North American plants belong to the polyploid Phleum pratense L. subsp. pratense, which differs from the diploid P. pratense subsp. bertolonii (DC.) Bornm. in having obtuse ligules. Depauperate specimens of P. pratense are hard to distinguish from P. alpinum (see next species).
2. Phleum alpinum L.
Alpine Timothy, Fléole Alpine, Phléole Alpine
Plants perennial; cespitose, sometimes shortly rhizomatous. Culms 15–50 cm, often decum-bent, lower internodes not en-larged or bulbous. Sheaths of the flag leaves inflated; auricles not developed, leaf edges some-times wrinkled at the junction of the sheath and blade; ligules 1–4 mm, truncate; blades to 17 cm long, 4–7 mm wide, flat. Panicles 1–6 cm long, 5–12 mm wide, usually 1.5–3 times as long as wide, subglobose to broadly cylindric, not tapering distally; branches adnate to the rachises. Glumes 2.5–4.5 mm, sides scabrous, keels hispid, apices awned, awns 0.8–2.5(3.2) mm; lemmas 1.7–2.5 mm, about 3/4 as long as the glumes, mostly glabrous, keels hairy, hairs to 0.1 mm; anthers 1–1.5(2) mm. 2n = 14, 28.
Phleum alpinum grows along stream banks, on moist prairie hillsides, and in wet mountain meadows. It is a circumboreal species extending, in the Flora region, from northern North America southward through the mountains to Mexico and South America. It is also widespread in northern Eurasia. Isolated, depauperate plants of P. pratense may be difficult to distinguish from P. alpinum; there is rarely difficulty in the field.
Kula et al. (2006) demonstrated that American and northern European plants of Phleum alpinum belong to the same taxon. They mistakenly identified the taxon as P. commutatum Gaudin. Because Humphries (1978) lectotypified P. alpinum on a plant from Lapland, that name has priority over P. commutatum. North American plants belong to P. alpinum L. subsp. alpinum and are tetraploid.
The count of 2n = 14 applies to Phleum alpinum subsp. rhaeticum Humphries, which grows in the mountains of central and southern Europe.
3. Phleum phleoides (L.) H. Karsten
Purple-Stem Cat’s Tail
Plants perennial; densely cespitose, not rhizomatous. Culms 6–90 cm, erect or nearly so, lower internodes not enlarged or bulbous. Sheaths of the flag leaves inflated; auricles not developed; ligules 1–2 mm, truncate, rounded, or obtuse; blades to 12(26) cm long, 1–6 mm wide, flat or convolute. Panicles 2–14(17) cm long, 4–10 mm wide, narrowly cylindrical, tapering distally; branches not adnate to the rachises. Glumes 2–3.7 mm, oblong-lanceolate, keels usually scabrous or shortly ciliate, sometimes smooth, apices not abruptly narrowed, awned, awns 0.3–0.5 mm; lemmas 2/3–3/4 as long as the glumes, glabrous or puberulent, apices acute; anthers about 1.5 mm. 2n = 14, 28.
Phleum phleoides is native to dry grasslands from Europe through central Asia. It was collected, in 1990, beside railroad tracks in Coquitlam, British Columbia.
4. Phleum paniculatum Huds.
Plants annual. Culms 5–30(55) cm, erect. Sheaths of the flag leaves not inflated; auricles not developed; ligules 5–7 mm, acute; blades to 19 cm long, 5–7 mm wide, flat or folded. Panicles 1–12 cm long, 3.5–7 mm wide, narrowly cylindrical, tapering somewhat distally. Glumes 1.5–2.5 mm, scabrous, inflated, keels sometimes slightly ciliate, margins ciliate distally, apices abruptly truncate, mucronate to awned, awns to 0.6 mm, lower glumes pilose on the margins; lemmas about 2/3 as long as the glumes, pubescent; anthers 0.3–0.5 mm. 2n = 28.
Phleum paniculatum is native to dry habitats in southern and south-central Europe. In the Flora region, it is known only from old ballast dump records.
5. Phleum subulatum (Savi) Asch. & Graebn.
Plants annual. Culms 2–30(40) cm. Sheaths of the flag leaves not inflated; auricles not developed, leaf edges often wrinkled at the junction of the sheath and blade; ligules 4–7 mm, acute; blades 1.5–12 cm long, 1–4 mm wide, sometimes convolute. Panicles 0.8–11 cm long, 2–7 mm wide, narrowly cylindrical, parallel-sided. Glumes 2–4 mm, semi-elliptical in outline, keels usually glabrous, apices of the lower and upper glumes pointing towards each other; lemmas about 2/3 as long as the glumes, glabrous, midveins scabridulous; anthers 1.5–2 mm. 2n = 14.
Phleum subulatum is native to the grasslands of southern Europe. In the Flora region, it is known only from old ballast dump records.
6. Phleum arenarium L.
Plants annual. Culms 2–35 cm. Sheaths of the flag leaves in-flated; auricles not developed; ligules 1.5–3 mm, rounded to acute; blades 1–5(7) cm long, 1.5–5 mm wide, flat or folded. Panicles 0.5–5.5 cm long, 3–7 mm wide, ovoid to shortly cylindrical, cuneate at the base, widest at or above midlength. Glumes 2.2–4.4 mm, oblong-lanceolate, keels ciliate, tapered, apices parallel or divergent, awns 0.3–1 mm, usually parallel, sometimes divergent; lemmas about 1/3 as long as the glumes, glabrous or pubescent; anthers 0.3–1.2 mm. 2n = 14.
Phleum arenarium is native to maritime sands and shingles of southern and western Europe. In the Flora region, it is known only from old ballast dump records.