Sporobolus pyramidatus |
Sporobolus coahuilensis |
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Madagascar dropseed, whorled dropseed |
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Habit | Plants annual, or short-lived perennials flowering in the first year; cespitose, not rhizomatous. | Plants annual. |
Culms | 7-35(60) cm, erect or decumbent. |
15-60 cm, ascending, glabrous. |
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. |
shorter than the internodes, glabrous; ligules 0.5-1 mm, ciliate; blades 4-12 cm long, 1.5-6 mm wide, flat, spreading, evenly distributed, adaxial surfaces sparsely ciliate-pustulate. |
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. |
6-22 cm long, (1)5-13 cm wide, open, sometimes contracted; branches terminating in a spikelet, lowest branches whorled, in verticels of 7-20; pedicels (2)3-6(8) mm, widely spreading, capillary. |
Spikelets | 1.2-1.8 mm, plumbeous or brownish, often secund along the branch. |
1.1-1.5 mm. |
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. |
thin, acute; lower glumes about 0.5 mm; upper glumes 1.1-1.5; lemmas 1.1-1.4 mm, acute; paleas 1-1.3 mm, hyaline. |
Fruits | 0.6-1 mm, obovoid, faintly striate, light brownish. |
0.6-0.9 mm, oblong, light brown; embryos 0.2-0.4 mm. |
2n | = 24, 36, 54. |
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Sporobolus pyramidatus |
Sporobolus coahuilensis |
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Distribution |
AR; AZ; CO; FL; IL; KS; LA; MD; MO; NE; NM; NY; OK; PA; TX; UT; HI; PR; Virgin Islands
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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 coahuilensis is primarily known from central Coahuila in Mexico. It has recently been found in Brewster and Hudspeth counties, Texas (Turner 2004). It is not clear whether it has been overlooked in the past or is a recent introduction. Sporobolus coahuilensis appears to be closely related to the widespread species S. pyramidatus, from which it differs in its long capillary pedicels and usually wider panicles. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 119. | FNA vol. 25. |
Parent taxa | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Sporobolus | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Sporobolus |
Sibling taxa | ||
Synonyms | S. pulvinatus, S. patens, S. argutus | |
Name authority | (Lam.) Hitchc. | Valdés-Reyna |
Web links |