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

POACEAE
809
inflorescence solitary, curved, 1-sided, dense, spike-like, 5–15 cm long; reduced
sterile florets present both below and above fertile floret ________________________ Ctenium
9. Upper glume without awn divergent at right angle to glume body; inflorescence
various; reduced sterile floret(s) present only below fertile floret.
10. Glumes equal; lemma of fertile floret strongly compressed, sharply keeled; reduced
florets 2 per spikelet, rudimentary or scale-like, their lemmas not similar
to the upper glume; inflorescence a very dense, tightly contracted, spike-like
panicle; disarticulation above glumes ____________________________________ Phalaris
10. Glumes usually unequal; lemma of fertile floret not as above; reduced floret 1
per spikelet (except 2 in Anthoxanthum), its lemma similar to the upper glume;
inflorescences various, spike-like to very different; disarticulation below glumes
(except above glumes in Anthoxanthum).
11. Reduced florets 2 per spikelet, these both awned; disarticulation above glumes;
plants with a sweet, vanilla-like fragrance (due to coumarin) _________ Anthoxanthum
11. Reduced floret 1 per spikelet, awned OR unawned; disarticulation below
glumes; plants without fragrance as described above _____________ Key H (page /811)
7. Reduced floret absent below the perfect floret (reduced florets found above the perfect
or absent or seemingly so).
12. Inflorescences unbranched or seemingly so (e.g. spikes or spike-like racemes).
13. Spikelets in clusters of 3 per node (the two lateral ones often reduced, staminate
or sterile), sessile.
14. Lemmas awned; inflorescence axis usually disarticulating at maturity, the
sections falling with the spikelets; spikes usually 4–10 cm long _____________ Hordeum
14. Lemmas awnless; inflorescence axis not disarticulating, a cluster of 3 spikelets
falling as a unit from the inflorescence axis; spikes 2–3.5 cm long ___________ Hilaria
13. Spikelets not 3 per node, sessile OR on pedicels.
15. Lemma with 3 awns _________________________________________________ Aristida
15. Lemma with 1 awn or awnless.
16. Inflorescence a narrow spike or spike-like raceme, with few spikelets.
17. Spikelets 4.5–7(–8) mm long; glumes subequal; ligule a membrane
1.5 mm or less long; disarticulation at nodes of inflorescence axis;
plants tufted annuals _______________________________________ Parapholis
17. Spikelets 2.1–3.4 mm long; lower glume absent; ligule of hairs 0.3
mm or less long; disarticulation below the glume(s) or not occurring;
plants rhizomatous mat-forming perennials _____________________ Zoysia
16. Inflorescence extremely dense, � cylindric, with numerous crowded
spikelets (actually very dense panicles).
18. Glumes awnless; lemma with awn 3–8+ mm long arising on back
below middle ____________________________________________ Alopecurus
18. Glumes awned; lemma awnless or with an awn to ca. 1 mm long
arising from the apex.
19. Awn of glumes 0.8–1.5(–2) mm long, abrupt from unnotched
apex; inflorescences 5–9(–10) mm wide; lemma awnless ___________ Phleum
19. Awn of glumes 4–10 mm long, from apical notch; inflorescences
10–30 mm wide; lemma with a delicate awn usually 0.5–1 mm
long _________________________________________________ Polypogon
12. Inflorescences branched (sometimes so dense that the branching is difficult to see).
20. Spikelets not borne along 1 side of the inflorescence branches; inflorescences
usually without distinct spike-like branches having spikelets to very base
(branches, however, can be so crowded as to make the whole inflorescence
appear spike-like); spikelets sessile or pedicelled ______________________ Key I (page /813)