Dichanthelium wilcoxianum |
Dichanthelium laxiflorum |
|
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fall panicum, fall rosette grass, Wilcox's panicgrass |
openflower rosette grass, soft-tuft panicgrass |
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Habit | Plants cespitose. | Plants densely cespitose. |
Culms | 15-35 cm, stiffly erect, all but the upper 2-4 internodes very short; nodes glabrous or with weak, reflexed hairs; internodes purplish-gray, sparsely pubescent; fall phase developing early, forming erect branches from the lower or midculm nodes, each branch terminating in a partially included panicle of 8-16 spikelets, no sterile shoots formed. |
15-55 cm, slender, erect or radiating from a large tuft of predominantly basal leaves, lower internodes short, upper 3-5 internodes elongate; nodes bearded with soft, spreading or retrorse hairs; internodes glabrous; fall phase branching extensively from the basal nodes, forming a dense cushion that overwinters. |
Cauline leaves | usually 3; sheaths hirsute, hairs papillose-based; ligules 0.5-1 mm; blades 4-8 cm long, 2-5 mm wide, all alike, stiffly erect, green to grayish-green, flat, not plicate, sparsely pilose. |
2-4; sheaths usually longer than the internodes, pilose, hairs to 4 mm, retrorse or spreading; ligules 0.2-1 mm, at low magnification appearing to be membranous and ciliate, at high magnification evidently of hairs that are coherent at the base; blades 4-17 cm long, 4-12 mm wide, lanceolate, at least 3/4 as long as the basal blades, spreading to suberect, thin, soft, lax, yellowish-green, nearly glabrous or densely pilose on 1 or both surfaces, margins usually finely short-ciliate, at least on the basal 1/2, cilia not papillose-based. |
Spikelets | 2.4-3.2 mm long, 0.7-1.2 mm wide, ellipsoid to obovoid, often reddish throughout, short-pubescent. |
1.7-2.3 mm long, 1-1.2 mm wide, broadly ovate or oblong-obovoid, with papillose-based hairs, obtuse. |
Lower glumes | 0.7-1.2 mm, triangular; upper glumes and lower lemmas about equaling the upper florets; upper florets 1.9-2.5 mm, ellipsoid, pointed. |
1/4 - 1/3 as long as the spikelets, broadly deltoid; upper glumes and lower lemmas subequal, usually fully covering the upper florets; upper florets 1.5-1.8 mm long, 1-1.2 mm wide, broadly ellipsoid or obovoid, minutely umbonate. |
Basal | rosettes poorly differentiated; sheaths glabrous; blades 2-4 cm, narrow, similar to those of the lower cauline leaves, ascending to spreading. |
rosettes poorly differentiated; blades ovate to lanceolate. |
Primary | panicles 3-5 cm long, 2-4 cm wide, ovoid, open, shortly exserted, with 12-32 spikelets; branches short, stiff, spreading; pedicels mostly 4-8 mm, spreading. |
panicles 4-12 cm long, 3-8 cm wide, well-exserted; secondary panicles more compact, usually not exserted above the crowded basal leaves; rachises and branches wiry, spreading or deflexed, often pilose. |
2n | = 18. |
= 18. |
Dichanthelium wilcoxianum |
Dichanthelium laxiflorum |
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Distribution |
CO; IA; IL; IN; KS; MN; MT; ND; NE; NM; OK; SD; WI; WY; AB; MB; SK
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AL; AR; DC; FL; GA; IL; IN; KY; LA; MD; MO; MS; NC; OH; OK; PA; RI; SC; TN; TX; VA; WV
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Discussion | Dichanthelium wilcoxianum grows in dry prairies, especially in sandy or gravelly openings. It is restricted to the Flora region. The primary panicles, which are produced from mid-May to early June, are partially open-pollinated; the secondary panicles, which are produced in June, and occasionally also in September, are cleistogamous. Some specimens of Dichanthelium oligosanthes subsp. scribnerianum from the southern Great Plains that have prematurely elongating upper internodes resemble D. wilcoxianum, but they have greenish spikelets that are 1.7-2.4 mm wide, an orange spot at the base of the glumes, and larger basal rosettes. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Dichanthelium laxiflorum is a widespread, common species that grows in mesic deciduous woods, and occasionally in drier, more open woodlands. Its range extends south from the Flora region into Mexico. The density of the pubescence on the blade surfaces varies greatly. The primary (spring) panicles are apparently chasmogamous; the secondary panicles are largely cleistogamous and are produced from late spring to winter. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 449. | FNA vol. 25, p. 446. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Dichanthelium > sect. Linearifolia | Poaceae > subfam. Panicoideae > tribe Paniceae > Dichanthelium > sect. Strigosa |
Sibling taxa | ||
Synonyms | Panicum wilcoxianum | Panicum ×alapense, Panicum laxiflorum |
Name authority | (Vasey) Freckmann | (Lam.) Gould |
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