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

ELEOCHARIS/CYPERACEAE
589
27. Spikelets relatively short, only (1.5–)3–7(–9) mm long even with age; leaf sheaths
and rhizomes usually not purplish red; distal leaf sheaths with apex inflated, loose,
thin-membranous and transparent, often conspicuously wrinkled, frequently disintegrating;
plants 42 cm or less tall _____________________________________ E. flavescens
27. Spikelets relatively long, usually at least (5–)7 mm long in flower, to 25 mm long
with age; leaf sheaths and rhizomes usually purplish red; distal leaf sheaths with
apex firm and opaque, neither inflated nor wrinkled, usually not disintegrating;
plants to 115 cm tall.
28. Culms round, internally hollow, completely and regularly septate with usually
externally visible septa ca. 2–5 mm apart; scales of spikelet 100–500+ per
spikelet, 1.5–2.7 mm long, 1–1.5 mm wide; achenes 0.7–1.1 mm long, the surface
with a distinct finely reticulate pattern; tubercle 0.2–0.35 mm long; distal
leaf sheath apex with a distinct tooth __________________________________ E. montana
28. Culms round to conspicuously flattened, spongy internally; scales of spikelet
15–100 per spikelet, 2–5.5 mm long, 1.5–2.5 mm wide; achenes (0.9–)1.1–1.9
mm long, the surface � smooth in appearance; tubercle 0.3–0.7 mm long;
distal leaf sheath apex with OR without a distinct tooth.
29. Lowermost scale of spikelets clasping 2/3(–3/4) of culm; all spikelets with
scale above the lowermost empty; culms round or slightly compressed
_____________________________________________________________ E. palustris
29. Lowermost scale of spikelets clasping 3/4 to all of culm; scale above the
lowermost with flower or empty; culms round to markedly compressed.
30. Scale above the lowermost scale of some spikelets empty; lowermost
scale of some or all spikelets usually clasping less than all of culm;
culms round to markedly compressed; anthers 1.3–2.7 mm long
____________________________________________________ E. macrostachya
30. Scale above the lowermost scale of all spikelets with flower; lowermost
scale of all spikelets clasping all of culm (amplexicaulous); culms
round; anthers 1–1.8 mm long ______________________________ E. erythropoda
22. Achenes trigonous (= 3-angled), sometimes bluntly so, to nearly rounded (definitely not
biconvex) in cross section; styles 3-branched; stigmas 3.
31. Tubercle huge, ca. as long and wide as achene; achenes coarsely honey-combed
reticulate ____________________________________________________________ E. tuberculosa
31. Tubercle much smaller than achene; achenes smooth to finely reticulate to coarsely
honey-combed reticulate.
32. Surface of achenes with a number of distinct ribs or ridges running lengthwise,
with fine horizontal lines between the ribs ____________________________________ E. wolfii
32. Surface of achenes smooth, without longitudinal ribs or ridges.
33. Achenes widest at apex, truncate, black or nearly so, with the tubercle flattish
across the entire apex (sometimes slightly wider than the achene) and with a
small central point; apex of distal leaf sheath truncate, with an abrupt awl-shaped
tooth; spikelets sometimes proliferating ____________________________ E. melanocarpa
33. Achenes not widest at apex, not truncate, variously colored, the tubercle narrower,
not stretching across the entire apex; apex of distal leaf sheath various;
spikelets not proliferating except in E. rostellata and E. vivipara.
34. Achenes constricted at summit to form a distinct narrow neck 0.2–0.3
mm long; species rare in East TX, known only from Hardin Co. ___________ E. elongata
34. Achenes variously shaped, often somewhat narrowed apically, but without
a distinct narrow neck; including species widespread and common
in East TX.