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rattail smutgrass, smut grass

tropical dropseed

Habit Plants perennial; cespitose, with tough fibrous roots, not rhizomatous. Plants annual; tufted.
Culms

30-100 (120) cm.

30-100 cm.

Sheaths

usually keeled below, glabrous;

ligules 0.2-0.5 mm;

blades (6)10-30(50) cm long, 1-5 mm wide, flat, glabrous on both surfaces.

glabrous, including the apices;

ligules 0.2-0.3 mm;

blades 5-23 cm long, 2-4 mm wide, flat or folded, glabrous on both surfaces, margins glabrous.

Panicles

20-35(50) cm long, 0.3-2.2(3) cm wide, contracted, narrow, sometimes included in the uppermost sheath;

primary branches 0.4-2.5(5) cm, appressed or spreading to 40° from the rachis, as long or longer than the adjacent internodes;

secondary branches appressed, spikelet-bearing to near the base;

pulvini glabrous;

pedicels 0.1-1.8 mm, appressed.

(8)15-30 cm long, 3.5-8 cm wide, open, diffuse, cylindrical;

lower nodes with 1-2(3) branches;

primary branches 0.6-5 cm, capillary, spreading 30-70° from the rachises, without spikelets on the lower 1/2;

secondary branches spreading;

pedicels 0.5-5 mm.

Spikelets

2-2.6(2.7) mm, plumbeous to light brownish.

0.7-1.1 mm, plumbeous to purplish.

Glumes

subequal, ovate or obovate, membranous;

lower glumes 0.5-1 mm, often without midveins;

upper glumes 0.8-1.6 mm, 1/2 - 2/3 as long as the florets, acute to obtuse, entire;

lemmas 1.8-2.6(2.7) mm, ovate, membranous, glabrous, acute or obtuse;

paleas 1.9-2.4 mm, ovate, membranous, glabrous;

anthers 3, 0.5-1.1 mm, white, sometimes purple-tinged.

unequal, obovate to ovate, membranous;

lower glumes 0.1-0.4 mm, occasionally absent;

upper glumes 0.2-0.5 mm;

lemmas 0.7-1.1 mm, elliptic, membranous, glabrous, acute to obtuse;

paleas 0.7-1.1 mm, elliptic, membranous;

anthers 0.2-0.3 mm, yellowish.

Fruits

1-1.2 mm, quadrangular, laterally compressed, reddish-brown, truncate.

0.4-0.7 mm, pyriform or quadroid, somewhat laterally flattened, light brownish to whitish.

2n

= 18, 24, 36.

= 12.

Sporobolus indicus

Sporobolus tenuissimus

Distribution
from FNA
AL; AR; CA; FL; GA; IL; KY; LA; MD; MI; MO; MS; NC; NJ; NY; OK; OR; PA; SC; TN; TX; VA; HI; PR; Virgin Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; SC; PR; Virgin Islands
[BONAP county map]
Discussion

Sporobolus indicus is a pantropical species. It commonly grows in disturbed places and open areas such as roadsides, pastures, and lake shores. In the Flora region, it is found on sandy or clay soils and is associated with many plant communities. The spikelets and upper leaves are often covered with hyphomycetous fungi (Bipolaris spp.); hence the common name of "smutgrass".

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

Sporobolus tenuissimus is native to the Western Hemisphere, and introduced to Africa and Asia. Its native distribution in the Americas is tropical, extending from southern Mexico to Brazil and Paraguay. It has been found at a few locations in the southeastern United States, at 0-100 m. It grows in disturbed areas, often occurring as a weed in gardens and cultivated fields.

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

Source FNA vol. 25, p. 122. FNA vol. 25, p. 118.
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. 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
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. pyramidatus, S. silveanus, S. teretifolius, S. texanus, S. vaginiflorus, S. virginicus, S. wrightii
Synonyms S. poiretii
Name authority (L.) R. Br. (Mart, ex Schrank) Kuntze
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