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

932 POACEAE/ERAGROSTIS
18. Plants perennial, with hardened bases; spikelets disarticulating so that
rachilla does not remain.
20. Lemmas keeled, the lateral veins conspicuous.
21. Lateral spikelets subsessile to short-pedicelled (peolicels on average
� 1 cm long); leaf blades 3–8 mm wide; plants hardened and
knotty at base and often with short rhizomes ________________ E. spectabilis
21. Lateral spikelets with long pedicels (on average � 1 cm long); leaf
blades 2–4 mm wide; plants hardened at base but neither knotty
nor with rhizomes _________________________________________ E. elliottii
20. Lemmas usually rounded on back (midvein visible, but lemma not
keeled), the lateral veins inconspicuous.
22. Spikelets 1.3–1.5 (or more) mm wide; lemmas 1.6–1.8 (or more)
mm long; fruits with a deep longitudinal groove; species widespread
in East TX; flowering May–Oct _______________________ E. intermedia
22. Spikelets 0.8–1.3 mm wide; lemmas 1.2–1.6 mm long; fruits
ungrooved or with a shallow longitudinal groove; species apparently
limited to Pineywoods in East TX; flowering mostly Nov–Jan
(–spring) __________________________________________________ E. lugens
17. Spikelets usually 1.5–10 mm wide; lemmas usually 1.8–4.4 mm long, keeled (in
most species) OR rounded on the back (in E. intermedia).
23. Lemmas rounded on back, the lateral veins inconspicuous; spikelets 4–6
(–7) mm long ________________________________________________ E. intermedia
23. Lemmas keeled, the lateral veins conspicuous; spikelets 4–18(–20) mm long.
24. Spikelets 3–10 mm wide, usually � 2 times as long as wide, conspicuously
flattened ______________________________________________ E. superba
24. Spikelets 3 mm or less wide, usually � 2 times as long as wide (often
several times), usually only slightly to moderately flattened.
25. Pedicels mixed, some longer and some shorter than the spikelets;
plants annual, with soft bases; spikelets disarticulating so that naked
zigzag rachilla (= axis of spikelet) and paleas remain after lemmas
and fruits have been shed ____________________________ E. pectinacea
25. Pedicels (almost all) longer than the spikelets; plants perennial, with
hardened bases; spikelets disarticulating so that rachilla does not
remain.
26. Main branches of inflorescence � smooth to the touch; anthers
0.9–1.6 mm long; lemmas 2.4–3.8 mm long; spikelets lanceolate
to ovate, usually with 10 or fewer florets; inflorescence
relatively long and narrow (usually more than 1.5 times as long
as wide) ____________________________________________ E. trichodes
26. Main branches of inflorescence scabrous to the touch; anthers
0.3–0.5 mm long; lemmas usually 1.4–2.3 mm long; spikelets
oblong to linear, usually with 7–30 florets; inflorescences relatively
short and broad (usually 1–1.5 times as long as wide).
27. Lateral spikelets subsessile to short-pedicelled, with
pedicels averaging less than 1 cm long; leaf blades 3–8
mm wide; plants hardened and knotty at base and often
with short rhizomes ______________________________ E. spectabilis
27. Lateral spikelets with pedicels on average more than 1 cm
long; leaf blades 2–4 mm wide; plants hardened at base
but neither knotty nor with rhizomes ___________________ E. elliottii