| Khidir W. Hilu |
Plants annual or perennial; cespitose.
Culms 10-150 cm, herbaceous, glabrous, branching both at and above the
base. Sheaths open; ligules membranous, ciliate. Inflorescences
terminal, panicles of (1)2-20 non-disarticulating, spikelike branches, exceeding
the upper leaves; branches 1-17 cm, all or most in a digitate cluster,
sometimes 1(2) branch(es) attached immediately below the terminal whorl, axes
flattened, terminating in a functional spikelet. Spikelets 3.5-11 mm,
laterally compressed, with 2-15 bisexual florets; disarticulation above
the glumes and between the florets (Eleusine
coracana not disarticulating).
Glumes unequal, shorter than the lower lemmas; lower glumes 1-3-veined;
upper glumes 3-5(7)-veined; lemmas 3-veined, glabrous, keeled,
apices entire, neither mucronate nor awned; paleas sometimes with winged
keels; anthers 3, 0.5-1 mm; ovaries glabrous. Fruits modified
caryopses, pericarp thin, separating from the seed at an early stage in its
development; seeds usually obtusely trigonous, the surfaces ornamented.
x = 8, 9, 10. Name from Eleusis, a Greek town where Demeter, the goddess
of harvests, was worshipped.
Eight of the nine species of Eleusine are native to Africa, where they
grow in mesic to xeric habitats; the exception, E.
tristachya, is native to South America. Three species have become established
in the Flora region. When moistened, the seeds of all species are easily
freed from the thin pericarp.
Eleusine coracana
subsp. africana, E. indica,
and E. tristachya are widely distributed
weeds. Eleusine coracana subsp. coracana
was domesticated in East Africa and subsequently introduced to India and China.
It is frequently grown for grain in India and Africa.
1 |
Panicles with 1-3 oblong branches 1-6(8) cm long,
attached in a single digitate cluster ..... 3. E.
tristachya |
Panicles with 4-20 linear branches 3.5-17 cm long, 1(2) of
the branches attached below the terminal, digitate cluster (2) |
|
| Lower glumes 1-veined; panicle branches 3-5.5 mm wide; surface of the seeds striate ..... 1. E. indica | |
Lower glumes 2- or 3-veined; panicle branches 5-15 mm wide;
surface of the seeds granular ..... 2. E.
coracana |
1. Eleusine indica (L.) Gaertn.
Goosegrass, Eleusine d'Inde
Plants annual. Culms 30-90 cm, erect or ascending, somewhat compressed;
lower internodes 1.5-2 mm thick. Sheaths conspicuously keeled, margins
often with long, papillose-based hairs, particularly near the throat; ligules
0.2-1 mm, truncate, erose; blades 15-40 cm long, 3-7 mm wide, with prominent,
white midveins, margins and/or adaxial surfaces often with basal papillose-based
hairs. Panicles with 4-10(17) branches, often with 1 branch attached as
much as 3 cm below the terminal cluster; branches (3.5)7-16 cm long, 3-5.5
mm wide, linear. Spikelets 4-7 mm long, 2-3 mm wide, with 5-7 florets,
obliquely attached to the branch axes. Lower glumes 1.1-2.3 mm, 1-veined;
upper glumes 2-2.9 mm; lemmas 2.4-4 mm; paleas with narrowly
winged keels. Seeds ovoid, rugulose and obliquely striate, usually not
exposed at maturity. 2n = 18.
Eleusine indica is a common weed in the warmer regions of the world. In
the Flora region, it usually grows in disturbed areas and lawns, and has
been found in most states of the contiguous United States.
2. Eleusine coracana (L.) Gaertn.
Plants annual. Culms to 62 cm, often branching; lower internodes
6-10 mm thick. Sheaths glabrous; ligules 1-2 mm, ciliate, with 1-2
mm hairs; blades 10-60 cm long, 6-12 mm wide, sometimes longer than the
culms, adaxial surfaces scabrous or pubescent. Panicles subdigitate, with
4-20 branches, 1(2) of the branches attached below the terminal cluster; branches
4-17 cm long, 5-15 mm wide, spreading at maturity. Spikelets 5-9 mm long,
3-6 mm wide, with 2-9 florets, sometimes not disarticulating at maturity. Lower
glumes 1.2-3 mm, 2- or 3-veined; upper glumes 2.2-6.5 mm; lemmas
2.2-5 mm; anthers about 1 mm. Seeds oblong-globose, granular, usually
exposed at maturity. 2n = 36.
Eleusine coracana is an allotetraploid, one of its genomes being derived
from E. indica. Two subspecies are recognized;
only subsp. coracana is known from North America.
1 |
Seeds almost globose, the surface granular to smooth; florets not disarticulating ..... subsp. coracana |
Seeds oblong, the surface shallowly ridged and uniformly
granular; florets disarticulating at maturity ..... subsp. africana |
Eleusine coracana subsp. africana (Kenn.-O'Byrne)
Hilu & de Wet
African Finger Millet, Finger Millet
Culms 21-62 cm. Blades 22-50 cm long, 6-10 mm
wide. Branches slim, 4-17 cm long, 5-7 mm wide. Spikelets 5-8
mm long, 3-4 mm wide, with 2-6 florets, disarticulating at maturity. Seeds
oblong, surfaces shallowly ridged, uniformly granular.
This weedy subspecies hybridizes freely with the cultivated subsp. coracana.
It tends to have more slender branches than subsp. coracana (5-7 mm wide
rather than 7-15 mm), which led to its previous inclusion in E.
indica.
Eleusine coracana (L.) Gaertn. subsp. coracana
Finger Millet, Ragi
Culms to 17 cm. Blades 30-60 cm long, 6-12 mm
wide. Branches 4-14 cm long, 7-15 mm wide, spikelets closely imbricate.
Spikelets 5-9 mm long, brown, with 6-9 florets, florets not disarticulating
at maturity. Seeds almost globose, brownish, surfaces granular to smooth.
Eleusine coracana subsp. coracana is the domesticated variant
of E. coracana. Biochemical data suggest that it evolved from a few populations
of the very variable subsp. africana.
It is cultivated at various agricultural experiment stations and occasionally
escapes.
Eleusine coracana subsp. coracana has a long historical record dating back at least 5000 years in Africa, and 3000 years in India. Five races, based on inflorescence morphology, are recognized in East Africa where it is widely cultivated for food and drink.
3. Eleusine tristachya (Lam.) Lam.
Threespike Goosegrass
Plants annual. Culms 10-45 cm, compressed. Blades 6-25 cm
long. Panicles digitate, with (1)2-3 branches; branches 1-6(8) cm
long, 5-14 mm wide, oblong. Spikelets 8-10 mm, with 5-9(11) florets. Glumes
unequal; lower glumes 2-3 mm; upper glumes 3-4 mm; lemmas
4-5 mm. 2n = 18.
Eleusine tristachya was originally thought to be native to tropical Africa
and introduced into tropical America, but it occurs in Africa only as a rare adventive.
It is now considered to be native to tropical America. In the 1800s and early
1900s, it was found on ballast dumps at various ports and transportation centers
in the United States. More recently, it has been found as a weed in the Imperial
Valley of California (Hilu 1980). All records of collections outside of California
appear to be historical, with no populations persisting. That from Texas, for
instance, was made from a plant growing in a range management area associated
with one of the Texas A&M University farms. Although not deliberately cultivated,
it probably was an escape. The species has not been collected since in Texas.