The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Madagascar dropseed, whorled dropseed

drop-seed, sacaton

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

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

10-250 cm, usually erect, rarely prostrate, 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.

open, usually glabrous, often ciliate at the apices;

ligules of hairs;

blades flat, folded, involute, sometimes terete.

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.

Inflorescences

terminal, open or contracted panicles, sometimes partially included in the uppermost sheath.

Spikelets

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

rounded to laterally compressed, with 1(-3) floret(s) per spikelet;

disarticulation above the glumes.

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.

0-1-veined;

calluses poorly developed, usually glabrous;

lemmas membranous or chartaceous, 1(3)-veined, unawned;

paleas glabrous, 2-veined, often splitting between the veins at maturity;

anthers (2)3.

Fruits

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

utricles or achenes, ellipsoid, obovoid, fusiform, or quadrangular, pericarp free from the seed, becoming mucilaginous when moist in most species, remaining dry and partially adherent to the seed in 5.

Heterolepis

and 5.

Clandestinus

.

Cleistogamous

spikelets occasionally present in the lower leaf sheaths, x = 9.

2n

= 24, 36, 54.

Sporobolus pyramidatus

Sporobolus

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
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; PR; AB; BC; MB; NB; NS; ON; PE; QC; SK; Virgin Islands
[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 is a cosmopolitan genus of more than 160 species that grow in tropical, subtropical, and warm-temperate regions throughout the world. Seventy-three species are native to the Western Hemisphere; 27 are native to the Flora region, three are established introductions, and one was introduced but has not persisted. Two genera of the Western Hemisphere, Calamovilfa and Crypsis, resemble Sporobolus in having hairy ligules, spikelets with 1 floret, 1-veined lemmas, and fruits with a free pericarp (Peterson et al. 1997).

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

Key
1. Plants annuals or short-lived perennials flowering in the first year.
→ 2
2. Lower panicle nodes with 7-20 branches
→ 3
3. Pedicels 0.1-0.5(1) mm long, appressed
S. pyramidatus
3. Pedicels 2(3)-6(8) mm long, widely spreading
→ Sporobolus coahuilensis
2. Lower panicle nodes with 1-3 branches
→ 4
4. Spikelets 0.7-1.1 mm long; anthers 0.2-0.3 mm long
S. tenuissimus
4. Spikelets 1.6-6 mm long; anthers 0.3-3.2 mm long.
→ 5
5. Mature panicles 10-35 cm long, 4.5-30 cm wide, open; secondary branches spreading; pedicels usually 6-25 mm long, spreading
S. texanus
5. Mature panicles 1-5 cm long, 0.2-0.5 cm wide, contracted; secondary branches appressed; pedicels usually 0.1-4 mm long, appressed.
→ 6
6. Lemmas strigose; spikelets 2.3-6 mm long; mature fruits (1.1)1.8-2.7 mm long
S. vaginiflorus
6. Lemmas glabrous; spikelets 1.6-3 mm long; mature fruits 1.2-1.8 mm long
S. neglectus
1. Plants perennial.
→ 7
7. Plants with rhizomes.
→ 8
8. Spikelets 1.4-3.2 mm long.
→ 9
9. Panicles 0.4-1.6 cm wide, spikelike, blades usually conspicuously distichous
S. virginicus
9. Panicles 2.4-8 cm wide, somewhat contracted to lax and open, blades not obviously distichous
S. fimbriatus
8. Spikelets 4-10 mm long.
→ 10
10. Panicles (0.6)1-8 cm wide, open to somewhat contracted, narrowly pyramidal, well-exerted from the uppermost sheath; branches without spikelets on the lower 1/3
S. interruptus
10. Panicles 0.04-1.6 cm wide, narrow or spikelike, partially to wholly included in the uppermost sheath; branches spikelet-bearing to the base.
→ 11
11. Fruits 1-2 mm long; pericarp gelatinous, slipping from the seed when wet; panicles 5-30 cm long, 0.4-1.6 cm wide; lemmas glabrous, smooth
S. compositus
11. Fruits (1.5)2.4-3.5 mm long; pericarp loose but neither gelatinous nor slipping from the seed when wet; panicles 5-11 cm long, 0.04-0.3 cm wide; lemmas minutely pubescent or scabridulous
S. clandestinus
7. Plants without rhizomes.
→ 12
12. Upper glumes usually less than 2/3 as long as the florets.
→ 13
13. Lower panicle branches much shorter than the adjacent internodes, appressed to strongly ascending
S. creber
13. Lower panicle branches usually as long as or longer than the adjacent internodes, appressed or ascending.
→ 14
14. Spikelets 2-2.7 mm long; upper glumes usually 1/2 - 2/3 as long as the florets, acute to obtuse, entire
S. indicus
14. Spikelets 1.3-1.8(2) mm long; upper glumes usually less than 1/2 as long as the florets, rarely longer; truncate, erose to denticulate.
→ 15
15. Anthers 0.9-1.1 mm long, usually 3, rarely 2; branches spikelet-bearing to the base
S. jacquemontii
15. Anthers 0.5-0.8 mm long, usually 2, rarely 3; branches without spikelets on the lower 1/4
S. diandrus
12. Upper glumes at least 2/3 as long as the florets, often longer.
→ 16
16. Spikelets 1-2.5(2.8) mm long [for opposite lead, see p. 117].
→ 17
17. Lower sheaths keeled and flattened below
S. buckleyi
17. Lower sheaths rounded below.
→ 18
18. Panicles 12-35 cm wide, open.
→ 19
19. Sheath apices with a conspicuous tuft of white hairs; flag blades nearly perpendicular to the culms
S. cryptandrus
19. Sheath apices glabrous or with a few scattered hairs; flag blades ascending.
→ 20
20. Secondary panicle branches spikelet-bearing to the base; pedicels mostly appressed, mostly 0.2-0.5 mm long; panicles 20-60 cm long
S. wrightii
20. Secondary panicle branches without spikelets on the lower 1/4 - 1/2; pedicels mostly spreading, mostly 0.5-25 mm long; panicles 10-45 cm long.
→ 21
21. Pedicels 0.5-2 mm long; anthers 1.1-1.8 mm long
S. airoides
21. Pedicels 6-25 mm long; anthers 0.3-1 mm long
S. texanus
18. Panicles 0.2-12(14) cm wide, contracted to open.
→ 22
22. Mature panicles 0.2-5 cm wide, contracted, often spikelike, the panicle branches appressed or diverging no more than 30° from the rachises.
→ 23
23. Primary panicle branches without spikelets on the lower 1/8–1/2 of their length.
→ 24
24. Leaf blades 1-1.5 mm wide; ligules 0.2-0.4 mm long
S. nealleyi
24. Leaf blades 2-6 mm wide; ligules 0.3-1 mm long.
→ 25
25. Lower panicle nodes with 7-12(15) branches; anthers 0.2-0.4 mm long
S. pyramidatus
25. Lower panicle nodes with 1-3 branches; anthers 0.5-1 mm long
S. cryptandrus
23. Primary panicle branches spikelet-bearing to the base.
→ 26
26. Lower glumes usually 1-veined; mature panicles 0.2-0.8(1) cm wide; lemmas 2-3.2 mm long, linear-lanceolate; upper glumes 2-3.2 mm long; anthers 3, 0.3-0.5 mm long; plants primarily from west of the Mississippi River
S. contractus
26. Lower glumes usually without veins; mature panicles 1-5 cm wide; lemmas 1.1-2 mm long, ovate; upper glumes 1.1-2 mm long; anthers 2 or 3, 0.5-1 mm long; plants primarily from east of the Mississippi River
S. domingensis
22. Mature panicles 4.5-30 cm wide, open, pyramidal to subovate or oblong, the panicle branches diverging more than 10° from the rachises, sometimes reflexed.
→ 27
27. Lower panicle nodes with 7-12(15) branches; anthers 0.2-0.4 mm long
S. pyramidatus
27. Lower panicle nodes with 1-2(3) branches; anthers 0.4-1 mm long.
→ 28
28. Pedicels 6-25 mm long, spreading; panicles 4.5-30 cm wide, about as long as wide, diffuse
S. texanus
28. Pedicels 0.1-3 mm long, appressed or spreading; panicles 0.3-14 cm wide, longer than wide, open and/or drooping.
→ 29
29. Culms 10-50(60) cm tall, 0.7-1.2 mm thick near the base; plants with hard, knotty bases; blades (0.6)1.5-6(7) cm long, 1-1.5 mm wide, involute, spreading at right angles to the culms
S. nealleyi
29. Culms 30-120 cm tall, 1-3.5 mm thick near the base; plant bases not hard and knotty; blades (2)5-26 cm long, 2-6 mm wide, flat to involute, ascending or at right angles to the culms.
→ 30
30. Pedicels appressed to the secondary branches; primary branches appressed, spreading, or reflexed; pulvini glabrous; rachises straight, erect; mature panicles narrowly pyramidal, lower branches longer than the middle branches
S. cryptandrus
30. Pedicels spreading from the secondary branches; primary branches reflexed; pulvini pubescent; rachises drooping or nodding; mature panicles subovate to oblong, lower branches no longer than those in the middle
S. flexuosus
16. Spikelets 2.5-10 mm long [for opposite lead, see p. 116].
→ 31
31. Lower panicle nodes with 3 or more branches.
→ 32
32. Mature panicles 2-6 cm wide, pyramidal; panicle branches diverging 20-100° from the rachises; blades 0.8-2 mm wide; fruits 1.4-1.8 mm long
S. junceus
32. Mature panicles 0.4-1.6 cm wide, narrow, contracted; panicle branches appressed or diverging to 20° from the rachises; blades 2-5 mm wide; fruits 1.8-2.3 mm long
S. purpurascens
31. Lower panicle nodes with 1-2(3) branches.
→ 33
33. Mature panicles 0.04-4 cm wide, spikelike; panicle branches appressed.
→ 34
34. Spikelets 4-6(10) mm long, stramineous to purplish-tinged; panicles terminal and axillary; sheaths without a conspicuous apical tuft of hairs.
→ 35
35. Lemmas minutely pubescent or scabridulous, chartaceous and opaque; pericarps loose but neither gelatinous nor slipping off the seeds when wet; fruits (1.5)2.4-3.5 mm long
S. clandestinus
35. Lemmas usually glabrous and smooth, membranous to chartaceous and hyaline; pericarps gelatinous, slipping off the seeds when wet; fruits 1-2 mm long
S. compositus
34. Spikelets 1.7-3.5(4) mm long, whitish to plumbeous; panicles all terminal; sheaths with a conspicuous apical tuft of hairs.
→ 36
36. Culms 40-100(120) cm tall, 2-4(5) mm thick near the base; mature panicles 0.2-0.8(1) cm wide; anthers 0.3-0.5 mm long
S. contractus
36. Culms 100-200 cm tall, (3)4-10 mm thick near the base; mature panicles 1-4 cm wide; anthers 0.6-1 mm long
S. giganteus
33. Mature panicles (0.6)1-30 cm wide, usually open, narrowly pyramidal to pyramidal or ovate; panicle branches appressed or spreading.
→ 37
37. Spikelets 2.3-3 mm long; panicles 4.5-30 cm wide, diffuse, about as long as wide; branches capillary; anthers 0.3-1 mm long
S. texanus
37. Spikelets 3-7.2 mm long; panicles 0.6-15 cm wide, longer than wide, not diffuse; branches not capillary; anthers 1.5-5 mm long.
→ 38
38. Mature spikelets plumbeous; sheath bases dull, fibrous.
→ 39
39. Anthers 3-4.2 mm long; ligules 0.2-0.7 mm long; plants from Arizona
S. interruptus
39. Anthers 1.7-3 mm long; ligules 0.1-0.3 mm long; plants not known from Arizona
S. heterolepis
38. Mature spikelets purplish-brown to purplish; sheath bases shiny, indurate.
→ 40
40. Blades 0.5-1.2 mm wide, subterete to terete in cross section, at least at the base, sometimes channeled for portions of their length, sometimes becoming tightly involute distally, senescing or turning tan in late fall, the margins smooth; pedicels with scattered ascending hairs
S. teretifolus
40. Blades 0.8-10 mm wide, flat or V-shaped in cross section, flat, folded, or involute when dry, remaining green well into winter or yellowing at maturity, the margins usually scabridulous, occasionally smooth; pedicels glabrous, sometimes scabridulous or scabrous.
→ 41
41. Lower glumes from 0.9 times as long as to longer than the upper glumes; culms 30-80(90) cm tall; panicles 10-25 cm long; pedicels 0.5-4(8) mm long, usually shorter than the spikelets, appressed
S. curtissii
41. Lower glumes from 0.6-0.9 (0.94) times as long as the upper glumes; culms (30)45-250 cm tall; panicles 15-50 cm long; pedicels 2-22 mm long, spreading or appressed.
→ 42
42. Pedicels appressed; lemmas 4.4-6.5 mm long; anthers 3.5-5 mm long; spikelets purplish
S. silveanus
42. Pedicels spreading; lemmas 3-4.3 mm long; anthers 2-3.4 mm long; spikelets purplish-brown.
→ 43
43. Blades (2)3-10 mm wide, pale bluish-green, yellowing at maturity; panicles (18)30-50 cm long, 4-15 cm wide; lower glumes (0.6)0.75-0.94 times as long as the upper glumes
S. floridanus
43. Blades 1.2-2(3) mm wide, dark green, remaining green well into winter; panicles 15-30 cm long, 2-6 cm wide; lower glumes 0.6-0.83 times as long as the upper glumes
S. pinetorum
Source FNA vol. 25, p. 119. FNA vol. 25, p. 115.
Parent taxa Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Sporobolus Poaceae > subfam. Chloridoideae > tribe Cynodonteae
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
Subordinate taxa
S. airoides, S. buckleyi, S. clandestinus, 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. tenuissimus, S. teretifolus, S. texanus, S. vaginiflorus, S. virginicus, S. wrightii
Synonyms S. pulvinatus, S. patens, S. argutus
Name authority (Lam.) Hitchc. R. Br.
Web links