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Madagascar dropseed, whorled dropseed

tussock dropseed

Habit Plants annual, or short-lived perennials flowering in the first year; cespitose, not rhizomatous. Plants perennial; cespitose, not rhizomatous.
Culms

7-35(60) cm, erect or decumbent.

30-80 cm.

Sheaths

rounded below, margins and apices hairy, hairs to 3 mm;

ligules 0.3-1 mm;

blades 2-12(20) cm long, 2-6 mm wide, flat, abaxial surface glabrous, adaxial surface scabridulous, sometimes sparsely hispid, margins ciliate-pectinate.

keeled or rounded;

ligules 0.2-0.5 mm;

blades 10-30 cm long, 2-4 mm wide, flat, becoming folded.

Panicles

4-15(18) cm long, 0.3-6 cm wide, open (contracted when immature), pyramidal;

lower nodes with 7-12(15) branches;

primary branches 0.5-4.5 cm, spreading 30-90° from the rachis, with elongated glands, without spikelets on the lower 1/3 – 1/2, secondary branches appressed;

pedicels 0.1-0.5 mm, appressed.

15-35 cm long, 0.4-4 cm wide, contracted to rather lax and open;

primary branches appressed to strongly ascending, without spikelets on the lower XA, lower branches much longer than the internodes;

pedicels 0.1-3 mm.

Spikelets

1.2-1.8 mm, plumbeous or brownish, often secund along the branch.

1.3-1.8 mm, plumbeous to greenish.

Glumes

unequal, ovate to obovate, membranous;

lower glumes 0.3-0.7 mm, without midveins;

upper glumes 1.2-1.8 mm, at least 2/3 as long as the florets, often longer;

lemmas 1.2-1.7 mm, ovate to elliptic, membranous, glabrous, acute;

paleas 1.1-1.6 mm, ovate to elliptic, membranous, glabrous;

anthers 0.2-0.4 mm, yellowish or purplish.

Fruits

0.6-1 mm, obovoid, faintly striate, light brownish.

0.7-0.9 mm, quadrangular, laterally compressed, reddish-brown, truncate.

Lower

glumes 0.4-0.8 mm, acuminate to truncate;

upper glumes 0.7-1 mm, usually less than H as long as the florets, rarely longer, faintly 1-veined, truncate, erose to denticulate;

lemmas 1.2-1.6(1.8) mm, elliptic, glabrous, 1-veined, acute to obtuse;

paleas 1.4-1.8 mm, elliptic;

anthers 2(3), 0.5-0.8 mm.

2n

= 24, 36, 54.

= 12.

Sporobolus pyramidatus

Sporobolus diandrus

Distribution
from FNA
AR; AZ; CO; FL; IL; KS; LA; MD; MO; NE; NM; NY; OK; PA; TX; UT; HI; PR; Virgin Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
HI
[BONAP county map]
Discussion

Sporobolus pyramidatus is native to the Americas, extending from the southern United States to Argentina. It grows in disturbed soils, roadsides, railways, coastal sands, and alluvial slopes in many plant communities, at elevations from 0-1500 m. Morphologically, it is very similar to the Eastern Hemisphere S. coromandelianus (Retz.) Kunth, suggesting that they are closely related.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Sporobolus diandrus is native from India to southeast Asia and Australia. It is not common in North America, being known only from a few counties in Florida, Mississippi, and Texas.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 119. FNA vol. 25, p. 124.
Parent taxa Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Sporobolus Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Sporobolus
Sibling taxa
S. airoides, S. buckleyi, S. clandestinus, S. coahuilensis, S. compositus, S. contractus, S. creber, S. cryptandrus, S. curtissii, S. diandrus, S. domingensis, S. fimbriatus, S. flexuosus, S. floridanus, S. giganteus, S. heterolepis, S. indicus, S. interruptus, S. jacquemontii, S. junceus, S. nealleyi, S. neglectus, S. pinetorum, S. purpurascens, S. silveanus, S. tenuissimus, S. teretifolius, S. texanus, S. vaginiflorus, S. virginicus, S. wrightii
S. airoides, S. buckleyi, S. clandestinus, S. coahuilensis, S. compositus, S. contractus, S. creber, S. cryptandrus, S. curtissii, S. domingensis, S. fimbriatus, S. flexuosus, S. floridanus, S. giganteus, S. heterolepis, S. indicus, S. interruptus, S. jacquemontii, S. junceus, S. nealleyi, S. neglectus, S. pinetorum, S. purpurascens, S. pyramidatus, S. silveanus, S. tenuissimus, S. teretifolius, S. texanus, S. vaginiflorus, S. virginicus, S. wrightii
Synonyms S. pulvinatus, S. patens, S. argutus S. indicus var. flaccidus
Name authority (Lam.) Hitchc. (Retz.) P. Beauv.
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