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Madagascar dropseed, whorled dropseed

Silveus' 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.

70-120 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.

shiny and indurate basally, glabrous or appressed hairy elsewhere, hairs to 4 mm;

ligules 0.2-0.8 mm;

blades 15-52 cm long, 1-2.5 mm wide, flat, folded or involute, bluish-green, remaining so well into winter, glabrous on both surfaces, margins scabridulous.

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.

21-50 cm long, 5-12(15) cm wide, longer than wide, open, not diffuse, pyramidal to ovate, with few spikelets;

lower nodes with 1-2(3) branches;

primary branches 6-20 cm, ascending, spreading 20-50° from the rachis, not capillary, without spikelets on the lower 1/4–1/2;

secondary branches appressed to loosely spreading;

pulvini glabrous;

pedicels 3-8(14) mm, longer or shorter than the spikelets, appressed, glabrous, scabrous.

Spikelets

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

4.5-7(7.2) mm, purplish.

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.

subequal to unequal, linear-lanceolate to lanceolate, membranous;

lower glumes 3-4.6 mm, 0.6-0.9 times as long as the upper glumes;

upper glumes 4-7.2 mm, from slightly shorter to longer than the spikelets;

lemmas 4.4-6.5 mm, lanceolate, membranous, glabrous, acuminate to acute;

paleas 4.5-6.7 mm, lanceolate, membranous, glabrous;

anthers 3, 3.5-5 mm, purplish.

Fruits

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

1.8-2.2 mm, obovoid, laterally flattened, light brownish.

2n

= 24, 36, 54.

= unknown.

Sporobolus pyramidatus

Sporobolus silveanus

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
FL; GA; LA; OK; TX
[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 silveanus is restricted to the southeastern United States. It grows in wet to mesic pine woodlands and adjoining glades and barren openings, and in black-land prairies, at elevations of 5-200 m.

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

Source FNA vol. 25, p. 119. FNA vol. 25, p. 137.
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. 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. tenuissimus, S. teretifolius, S. texanus, S. vaginiflorus, S. virginicus, S. wrightii
Synonyms S. pulvinatus, S. patens, S. argutus
Name authority (Lam.) Hitchc. Swallen
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