Panicum bergii |
Panicum diffusum |
|
---|---|---|
Berg's panicgrass, Bergs witchgrass |
spreading witchgrass, West Indian panicgrass |
|
Habit | Plants perennial; cespitose, with numerous leaves clustered at the base. | Plants perennial; cespitose and shortly rhizomatous. |
Culms | (10)50-140 cm, stout, stiffly erect, branched from the middle and lower nodes; lower nodes sericeous; lower internodes sericeous, hairs papillose-based, upper internodes sometimes glabrous. |
(6)25-100 cm, 0.5-3.5 mm thick, spreading to weakly ascending, usually freely branching; nodes pilose, hairs spreading to ascending; internodes pilose, with papillose-based hairs, or sparsely hispid. |
Sheaths | rounded, glabrous or sparsely to densely hispid, hairs not fragile and prickly, not causing skin irritation, margins ciliate; ligules 1-3 mm; blades 3-60 cm long, 2-12 mm wide, flat or involute, ascending, adaxial surfaces densely hirsute basally, less densely so elsewhere, bases attenuate, apices acute. |
rounded, glabrous, margins shortly ciliate distally; ligules 0.6-4 mm, of hairs; blades (3)6-15 cm long, 1-5 mm wide, spreading, abaxial surfaces sparsely hirsute, adaxial surfaces more densely so, hairs papillose-based, midribs prominent and not white, margins involute, bases cuneate, apices subulate. |
Panicles | (4)15-40 cm long, (3)10-25 cm wide, about 1/3 – 1/2 as long as the plants, open, breaking at the base of the peduncles at maturity and dispersed as tumbleweeds, secondary branching mostly confined to the distal 1/3 of the primary branches; rachises densely hispid or glabrous; lower primary branches in whorls of 4-7, stiffly spreading, naked on the lower 1/2; pedicels 3-20 mm, appressed. |
|
Spikelets | 2-3 mm long, 0.8-1.2 mm wide, glabrous. |
2.1-2.9 mm long, 0.8-1 mm wide, glabrous. |
Lower glumes | 1-1.6 mm, 5-veined, acuminate; upper glumes and lower lemmas similar, 2-2.8 mm, 7-9-veined, exceeding the upper florets by about 0.3 mm; lower florets sterile; lower paleas 1.4-2.2 mm; upper florets 1.5-1.9 mm long, 0.7-1 mm wide, smooth, chestnut brown at maturity. |
1-1.2 mm, to 1/2 as long as the spikelets, attenuate, 5-9-veined, veins anastomosing apically; upper glumes and lower lemmas similar, extending about 0.5 mm beyond the upper florets, 11-13-veined; lower florets sterile; lower paleas 1-1.3 mm; upper florets 1.5-1.8 mm long, 0.6-0.8 mm wide, smooth. |
Terminal | panicles 3-35 cm long, about 1/2 as wide, shortly exserted; axillary panicles smaller, not fully exserted; rachises scabridulous; primary branches usually solitary, sometimes paired, divergent and widely spaced, secondary branching mostly on the distal 1/3 of the primary branches; pedicels 1-4 mm, spreading to appressed, confined to the distal portions of the secondary branches. |
|
2n | = 36. |
= 36. |
Panicum bergii |
Panicum diffusum |
|
Distribution |
AL; GA; LA; TX |
LA; TX; PR; Virgin Islands |
Discussion | Panicum bergii is an eastern South American species that now grows in southeastern Texas. It occurs in ditches and shallow, and sporadically flooded depressions in grasslands. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Panicum diffusum grows along river banks, ditches, and disturbed areas in wet, loamy or clayey soils. Its range extends from Texas to the Caribbean and northern South America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 464. | FNA vol. 25, p. 466. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum |
Sibling taxa | ||
Synonyms | P. pilocomayense | |
Name authority | Arechav. | Sw. |
Web links |