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broom bluestem, little bluestem

Habit Plants cespitose or rhizomatous, green to purplish, sometimes glaucous.
Culms

7-210 cm tall, usually 1-3 mm thick, not rooting or branching at the lower nodes.

Sheaths

rounded or keeled, glabrous or pubescent, sometimes glaucous;

ligules 0.5-2 mm, collars neither elongate nor narrowed;

blades 7-105 cm long, 1.5-9 mm wide, without a longitudinal stripe of white, spongy tissue.

Peduncles

0.8-10 cm;

rames 2.5-8 cm, partially to completely exserted, usually somewhat open;

internodes 3-7 mm, usually arcuate at maturity, ciliate on at least the distal 1/2 (sometimes throughout), hairs 1.5-6 mm.

Pedicels

3-7.5 mm long, 0.1-0.2 mm wide at the base, flaring above midlength to 0.3-0.5 mm, straight or curving outwards.

Sessile

spikelets 3-11 mm;

calluses 0.5-1(2) mm, hairs 0.3-4 mm;

lower glumes glabrous;

upper lemmas membranous throughout, cleft to 1/2 their length;

awns 2.5-17 mm.

Pedicellate

spikelets 0.7-10 mm, sometimes shorter than the sessile spikelets, sterile or staminate, unawned or awned, awns to 4 mm, when sterile, the lemma usually absent.

2n

= 40.

Schizachyrium scoparium

Distribution
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; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; AB; BC; MB; NB; NS; ON; QC; SK
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Discussion

Schizachyrium scoparium is a widespread grassland species extending from Canada to Mexico. It is one of the principal grasses in the tallgrass prairies that used to dominate the central plains of North America. It exhibits considerable variation, much of it clinal. The following varieties are recognized because they are morphologically, ecologically, and geographically distinctive.

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

Key
1. Plants not cespitose, strongly rhizomatous; pedicellate spikelets sterile
var. stoloniferum
1. Plants usually cespitose, not or shortly rhizomatous; pedicellate spikelets staminate or sterile.
→ 2
2. Pedicellate spikelets of the proximal spikelet units on each rame staminate, 5-10 mm long, with a lemma, pedicellate spikelets of the distal units usually smaller (1-4 mm) and sterile; sheaths and blades densely tomentose to glabrate
var. divergens
2. Most pedicellate spikelets sterile, 1-6 mm long, without a lemma; sheaths and blades usually glabrous, occasionally pubescent
var. scoparium
Source FNA vol. 25, p. 669.
Parent taxa Poaceae > subfam. Panicoideae > tribe Andropogoneae > Schizachyrium
Sibling taxa
S. cirratum, S. littorale, S. maritimum, S. niveum, S. rhizomatum, S. sanguineum, S. spadiceum, S. tenerum
Subordinate taxa
S. scoparium var. divergens, S. scoparium var. scoparium, S. scoparium var. stoloniferum
Synonyms Andropogon scoparius
Name authority (Michx.) Nash
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