Dichanthelium strigosum |
Dichanthelium acuminatum |
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cushion-tuft panicgrass, roughhair rosette grass |
hairy panic grass, hairy perennial panicgrass, hairy rosette-panicgrass, hotsprings rosette grass, panic laineux, tapered rosette grass, western witchgrass, woolly panic grass, woolly witchgrass |
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Habit | Plants densely cespitose. | Plants more or less densely cespitose. | ||||||||||||||||||||||||||||||||||||||||||||
Culms | 5-45 cm, slender, erect or spreading; from a dense tuft of predominantly basal leaves, lower internodes short, upper 3-5 internodes elongate; nodes glabrous or bearded; internodes glabrous or pilose; fall phase with spreading culms and branches arising from near the bases forming a dense, flat tuft. |
15-100 cm (rarely taller), usually thicker than 1 mm, weak and wiry or relatively stout and rigid, erect, ascending or decumbent; nodes occasionally swollen, glabrous or densely pubescent, often with a glabrous or viscid ring below; internodes purplish or olive green or grayish-green, to yellowish-green, variously pubescent, with hairs of 2 lengths or glabrous; fall phase erect, spreading, or decumbent, usually branching extensively at all but the uppermost nodes, ultimately forming dense fascicles of branchlets with reduced, flat or involute blades and reduced secondary panicles with few spikelets. |
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Cauline leaves | 2-4; lower cauline sheaths longer than the internodes, mostly glabrous or pilose with ascending hairs, margins finely ciliate; ligules 0.2-2 mm, at low magnification appearing to be membranous and ciliate, at high magnification evidently of hairs that are coherent at the base; blades 1.5-6 cm long, 3-8 mm wide, lanceolate, glabrous or softly pilose, margins with prominent papillose-based cilia, at least basally. |
4-7; sheaths usually shorter than the internodes, glabrous or densely and variously pubescent with hairs shorter than 3 mm, margins ciliate or glabrous; ligules and pseudoligules 1-5 mm, of hairs; blades 2-12 cm long (rarely longer), 2-12 mm wide (rarely wider), firm or lax, spreading to reflexed or stiffly ascending, yellowish-green or grayish-green to olivaceous, densely to sparsely and variously pubescent, margins similar or occasionally whitish-scabridulous, margins often with papillose-based cilia, at least basally, bases rounded or subcordate. |
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Spikelets | 1.1-2.1 mm, obovoid to broadly ellipsoid, glabrous or pubescent, hairs not papillose-based. |
1.1-2.1 mm, obovoid to ellipsoid, yellowish-green to olivaceous or purplish, variously pubescent, obtuse or subacute. |
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Lower glumes | 1/3 - 1/2 as long as the spikelets, acute to obtuse; upper florets 0.8-1.7 mm, ellipsoid, subacute. |
usually 1/4 - 1/2 as long as the spikelets, obtuse to acute; upper glumes and lower lemmas subequal, equaling the upper florets at maturity, or occasionally the upper glumes slightly shorter, not strongly veined; lower florets sterile; upper florets 1.1-1.7 mm long, 0.6-1 mm wide, ellipsoid, obtuse to acute or minutely umbonate or apiculate. |
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Basal | rosettes poorly differentiated; blades 1-5 cm, lanceolate, grading into the cauline blades. |
rosettes usually well-differentiated; blades ovate to lanceolate. |
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Primary | panicles short- to long-exserted; rachises and branches often pilose. |
panicles 3-12 cm, 1/4 - 3/4 as wide as long, usually open, well-exserted, rather dense; rachises glabrous, puberulent, or more or less densely pilose, at least basally. |
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2n | = 18. |
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Dichanthelium strigosum |
Dichanthelium acuminatum |
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Distribution |
AL; FL; GA; LA; MS; NC; SC; TN; TX; VA; PR
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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
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Discussion | Dichanthelium strigosum extends from the southeastern Flora region south into Mexico, the Caribbean, and into northern South America. The primary panicles are briefly open-pollinated in April or May; the secondary panicles, which are produced from May through November, are cleistogamous. The three subspecies are mostly sympatric and sometimes grow together, with occasional intergradation. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Dichanthelium acuminatum is common and ubiquitous in dry to wet, open, sandy or clayey woods, clearings, bogs, and swamps, or in saline soil near hot springs, growing in much of the Flora region and extending into northern South America. It is probably the most polymorphic and troublesome species in the genus. The treatment presented here attempts to delimit the major variants present, but does not fully reflect the intricate reticulate pattern of morphological variation that exists. There is considerable overlap among the nine subspecies recognized and, in addition, there appears to be widespread introgression from other Dichanthelium species, such as D. dichotomum, D. sphaerocarpon, D. ovale, and D. aciculare into the D. acuminatum complex, contributing to the taxonomic difficulties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 446. | FNA vol. 25, p. 422. | ||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Dichanthelium > sect. Strigosa | Poaceae > subfam. Panicoideae > tribe Paniceae > Dichanthelium > sect. Lanuginosa | ||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Panicum strigosum | Panicum acuminatum, Panicum lanuginosum | ||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Muhl. ex Elliott) Freckmann | (Sw) Gould & C.A. Clark | ||||||||||||||||||||||||||||||||||||||||||||
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