Poa cuspidata |
Poa chapmaniana |
|
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early bluegrass |
Chapman's blue grass |
|
Habit | Plants perennial; loosely tufted or with solitary shoots, shortly rhizomatous. | Plants annual; densely tufted, tuft bases narrow, not stoloniferous, not rhizomatous. |
Culms | 15-60 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed; nodes terete, 0-1 exserted. |
5-30(40) cm tall, 0.3-0.7 mm thick, erect or the bases geniculate; nodes terete, usually 1 exserted. |
Sheaths | closed for about 1/2 their length, slightly compressed, distinctly keeled, glabrous, bases of basal sheaths glabrous, distal sheath lengths 4-60 times blade lengths; collars of proximal leaves usually retrorsely scabrous or pubescent distally and about the throat; ligules 0.5-4 mm, smooth or scabrous, apices truncate to acute; innovation blades similar to the cauline blades; cauline blades 1-4 mm wide, usually flat, sometimes slightly folded, smooth or sparsely scabrous, primarily over the veins, apices broadly prow-shaped, blades steeply reduced in length distally, flag leaf blades 0.2-3(6) cm. |
closed for 1/10 – 1/2 their length, terete or weakly compressed, smooth; ligules 0.7-5 mm, decurrent, truncate to acute; blades of innovations and culms similar, 2-5(8) cm long, 0.6-2.8 mm wide, flat or folded, thin, soft, smooth, margins scabrous, apices narrowly prow-shaped. |
Basal branching | mainly extravaginal. |
|
Panicles | 5-15 cm, erect or lax, pyramidal, open, sparse, with 20-80 spikelets, proximal internodes usually 3+ cm; nodes usually with 2 branches; branches (2)3-7(10) cm, spreading to reflexed, straight, angled, angles scabrous, with 2-8(10) spikelets. |
2-9.6 cm, erect, eventually open, moderately to densely congested, with 1-4(7) branches per node; branches eventually ascending to spreading, rarely reflexed, terete, smooth or sparsely scabrous, spikelet-bearing to near the base or middle. |
Spikelets | 5-8 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic; florets 2-5; rachilla internodes smooth. |
(2)2.4-4.5 mm, laterally compressed; florets (1)2-6; rachilla internodes usually shorter than 0.7 mm, smooth or scabrous, glabrous. |
Glumes | narrowly lanceolate to lanceolate, distinctly keeled; lower glumes 1-3-veined; calluses webbed, hairs over 1/3 the lemma length; lemmas 3-6 mm, lanceolate, distinctly keeled, keels and marginal veins sparsely short- to long-villous, lateral veins moderately prominent, intercostal regions glabrous or the upper florets in the spikelets softly puberulent, margins glabrous, apices acute; palea keels scabrous, softly puberulent at midlength; anthers vestigial (0.1-0.2 mm) or 2-3.5 mm. |
subequal, about 3/4 as long as to subequal to the adjacent lemmas, lanceolate, thin, distinctly keeled, keels scabrous; lower glumes 1-3-veined; calluses webbed; lemmas 1.9-3 mm, broadly lanceolate, distinctly keeled, smooth, keels and marginal veins short- to long-villous, hairs on the keels extending to near the apices, lateral veins obscure, usually softly puberulent, intercostal regions usually sparsely softly puberulent, apices obtuse to acute; palea keels softly puberulent to long-villous at midlength, scabrous near the apices; anthers 1, 0.1-0.2(0.3) mm. |
2n | = 28. |
= unknown. |
Poa cuspidata |
Poa chapmaniana |
|
Distribution |
AL; DC; DE; GA; IN; KY; LA; MD; NC; NJ; NY; OH; PA; SC; TN; VA; WV
|
AL; AR; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MO; MS; NC; NE; NY; OH; OK; SC; TN; TX; VA; WV |
Discussion | Poa cuspidata is a common species of forest openings in the Appalachian Mountains. It is an eastern counterpart of P. arnowiae (see previous), P. tracyi (p. 543), and P. nervosa (see next). Like those species, it is sequentially gynomonoecious. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Poa chapmaniana is native from the central part of the Great Plains east and southward to the coast. It grows in dry to mesic forests, forest openings, and the margins of bottomlands, often in disturbed ground and on acidic substrates. Records from New York probably represent introductions. Its web and single short anther distinguish P. chapmaniana from P. annua (p. 520) and most plants of P. bigelovii. It also differs from P. bigelovii (see below), probably its closest relative, in having narrower leaf blades, and panicle branches that are eventually spreading. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 545. | FNA vol. 24, p. 534. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Madropoa > subsect. Poa | Poaceae > subfam. Pooideae > tribe Poeae > Poa > subg. Poa > sect. Homalopoa |
Sibling taxa | ||
Name authority | Nutt. | Scribn. |
Web links |