 | Inflorescence a panicle with all spikelets subtended by 2 glumes; NOT
[Inflorescence a terminal spike; lateral spikelets positioned edgewise
to the rachis and lacking a glume on inside edge] |
 | Spikelets usually pedicellate; if sessile-subsessile, then not
arranged as below; NOT [Spikelets sessile or subsessile on spike-like
panicle branches, or on short secondary branches in dense one-sided
clusters at branch tips] |
 | Rachillas glabrous or pubescent; if pubescent, then hairs much shorter
than the lemmas; panicles and plants not as below; NOT [Rachillas with
silky hairs (4) 6-10 mm long, as long as the lemmas or nearly so;
panicles 15-35 (45) cm long, 8-20 cm wide at maturity, dense, feathery;
plants 10-30 (40) dm tall, with stout, creeping rhizomes and often
forming dense stands] |
 | Glumes < 17 mm long; if glumes longer, then plants perennial; NOT
[Glumes 18-32 mm long, usually exceeding the lemmas; plants annual] |
 | Plants without the below combination of characteristics; NOT [Culm
sheaths closed to near summit; leaf blades flat; spikelets 12-40 (55) mm
long; lemmas 7-14 (21) mm long, usually awned, the awns terminal or
subterminal; calluses glabrous; ovaries and caryopses with pubescent
apical appendage; caryopses adnate to paleas at maturity] |
 | Plants without the below combination of characteristics; NOT [Rachilla
conspicuously pubescent with straight hairs; calluses bearded; spikelet
2 (3-4) flowered; lemma 2-4 toothed, sometimes obscurely so, sometimes
entire; lemma awns attached dorsally or just below apex, often exceeding
the lemma apex by only 1-2 mm (awn may be absent in Trisetum wolfii)] |
 | Lemmas unawned or awned; if awns present, then the awns straight and
terminal or subterminal, and the calluses glabrous or with short, sparse
hairs; NOT [Lemmas awned, the awns 3-17 mm long, slightly outcurving or
geniculate, attached dorsally about midlength, or at base of 0.5-8 mm
long apical teeth; calluses with dense or long hairs] |
 | Lemmas with 5 - 11 visibly-raised nerves or nerves too obscure to
count; NOT [Lemmas with 3 visibly-raised nerves (1 midnerve and 2
lateral nerves)] |
 | Lemmas not as below, either keeled, or with obscure nerves or nerves
converging distally; calluses glabrous or pubescent; NOT [Lemmas rounded
or weakly keeled on the back, with 5-11 visibly- raised nerves that are
+/- parallel their full length, their tips not converging distally;
calluses glabrous] |
 | Plants not as below; NOT [Plants low (to 4 (6) dm high), halophytic,
dioecious perennials with scaly, stout, creeping, much-branched
rhizomes; leaf blades strongly 2-ranked, 1-12 (20) cm long, reaching or
exceeding at least the panicles; lemmas of flowers coriaceous, closely
imbricate; caryopses long-beaked, the dark tip often visible between the
pale-colored lemma and palea] |
 | Plants growing in dry or wet habitats but not typically in water;
rhizomes present or absent; culms slender and not particularly spongy at
base; other features various; NOT [Plants growing in shallow water or
wetlands; rhizomes extensive, creeping, thick, soft, succulent; culms
thick (6 - 8 mm wide) and spongy at base; leaf sheaths open, large,
papery, +/- inflated, the lower sheaths often cross-septate with air
chambers; calluses densely bearded; lemma unawned but sometimes with
nerves excurrent at tip] |
 | Glumes not as below; disarticulation above the glumes; other features
various; NOT [Upper and
lower glumes markedly dissimilar in shape, the lower glume subulate to
linear and less than 1/3 as wide as the upper; the upper glume
oblanceolate to obovate, and about 1/2 as wide to nearly as wide as
long; spikelets 2-4 mm long, 2-3-flowered; disarticulation below the
glumes with the distal floret sometimes falling before the spikelet] |
 | Spikelets (1) 2-11 (15)-flowered; upper glume length various but if
reaching the tip of the distal lemma, then glumes (6) 7-8.5 (9.5) mm
long; rachises and panicle branches scabrous on the angles or smooth but
not pubescent; sheaths open or closed part way; NOT [Spikelets (1) 2-3
(4)-flowered; upper glume as long as the lowest lemma and sometimes
reaching the tip of the distal lemma, 3-4 (5.5) mm long; rachises and
panicle branches densely puberulent to villose; sheath open to base] |
 | Lemmas mucronate or awned from the tip except sometimes lacking awns
and mucros in plants with glumes reaching the tip of the distal lemma
and in plants with soft auricles present on leaves at base of plant; NOT
[Lemmas lacking mucros or awns; glumes distinctly shorter than the
lemmas, and plants lacking auricles] |
 | Plants perennial; NOT [Plants annual] |
 | Auricles absent or present as bumps or swellings; leaf blades usually
folded or rolled at maturity and to about 2.5 mm in diameter; culms
(0.5) 1–9 (14) dm high; NOT [Auricles present; leaf blades flat at
maturity, 2-7 mm wide; culms (3) 5-10 (13) dm high]
|