keys to the vascular plants of east texas - Botanical Research ...

ERAGROSTIS/POACEAE
931
8. Inflorescences 15 cm or less long, with main branches ca. 3 cm or less long, the
branches either not easily discernible (because they are short and dense) OR
ascending-spreading; palea keels ciliate, the cilia 0.2–0.8 mm long.
9. Inflorescences so dense that they cannot be seen through; pedicels 0.1–1
mm long, usually shorter than the spikelets, straight; spikelets with 6–12 florets;
anthers 2 ______________________________________________________ E. ciliaris
9. Inflorescences dense, but generally able to be seen through; pedicels 1–4
(–7) mm long, usually as long as or longer than the spikelets, typically with a
noticeable curvature; spikelets with 4–8 florets; anthers 3 _________________ E. amabilis
7. Spikelets (4–)5–20 mm long, large enough or loosely arranged enough so that
the individual spikelets are easily discernable at arm’s length.
10. Spikelets usually 1–1.5(–2) mm wide, almost as thick as wide, linear in outline
_________________________________________________________________ E. barrelieri
10. Spikelets 2–5 mm wide, much wider than thick, ovate to lanceolate in outline.
11. Plants annual; margins of leaf blades, culms just below nodes, and usually
keels of lemmas and glumes glandular-dotted (use hand lens or dissecting
scope); spikelets 2–4 mm wide, flattened but not strongly so; lemmas
2–2.8 mm long, apically obtuse to acute ____________________________ E. cilianensis
11. Plants perennial; margins of leaf blades, culms just below nodes, and lemmas
and glumes not glandular-dotted; spikelets 3–5 mm wide, strongly
flattened; lemmas 2.2–4 mm long, apically acuminate or nearly so _____ E. secundiflora
4. Main branches of inflorescence naked for a distance from base; inflorescences usually relatively
open and broad with loosely ascending to widely spreading branches (inflorescence
can be narrow in E. secundiflora, E. superba, and E. curvula).
12. Pedicels longer than spikelets; spikelets widely spreading from branches.
13. Spikelets 2–5(–6)-flowered, 2–4 mm long.
14. Leaf sheaths glabrous (except on margins and at apex).
15. Plants annual, with soft bases; leaf blades 1–4(–5) mm wide; lemmas 1.2–
1.7 mm long, keeled; culms usually 50 cm or less tall ____________________ E. capillaris
15. Plants perennial, with hardened bases; leaf blades 4–10 mm wide; lemmas
1.8–2.4 mm long, rounded on the back (sometimes slightly keeled near
tip); culms usually 45–130 cm tall ____________________________________ E. hirsuta
14. Leaf sheaths hairy on the surfaces (as well as at the margins and the apex).
16. Culms usually 45–130 cm tall; leaves not crowded at base of culms; leaf
blades (8–)25–40(–60) cm long; species widespread in East TX ____________ E. hirsuta
16. Culms usually less than 60 cm tall; leaves crowded at base of culms; leaf
blades 8–12 cm long; species rarely, perhaps questionably, present in East
TX __________________________________________________________ E. polytricha
13. Spikelets (4–)5–30-flowered, 3–18 mm long.
17. Spikelets very narrow, 1.5 mm or less wide; lemmas 1.2–1.8 mm long, rounded
on the back OR keeled.
18. Plants annual, with soft bases; spikelets disarticulating so that naked zigzag
rachilla (= axis of spikelet) (and sometimes paleas) remains after lemmas
and fruits have been shed.
19. Closed spikelets (before lemmas spread open) 1 mm wide or less; lower
glume 1/4–1/2 as long as adjacent lemma; lemmas 1.2–1.6 mm long;
leaf blades 0.4–2.2(–3) mm wide; lower inflorescence branches hairlike,
usually verticillate (in whorls of 3 or more branches) _______________ E. pilosa
19. Closed spikelets over 1 mm wide; lower glume 1/2–3/4 as long as adjacent
lemma; lemmas more than 1.6 mm long; leaf blades 3–7 mm
wide; lower inflorescence branches 1–3, usually not verticillate, if somewhat
verticillate then not hair-like _____________________________ E. pectinacea