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

580 CYPERACEAE/CYPERUS
Cyperus squarrosus L., (with recurved tips), BEARDED FLAT SEDGE, AWNED FLAT SEDGE. Tufted annual
usually 3–20 cm tall, with persistent odor when crushed or dried, like coffee-and-chicory
or curry powder (even after decades in a herbarium); inflorescences with spikelets in 1–3, often
essentially sessile, head-like clusters, the spikelets � digitately arranged or sometimes along a
short axis; scale tips prominently recurved; achenes usually 0.7–1 mm long. Disturbed soils,
sand; widespread in TX; s Canada and throughout the U.S. and � cosmopolitan. Jun–Jul. [C.
aristatus Rottb., C. inflexus Muhl., C. squarrosus var. runyonii (O’Neill) S.D. Jones & Wipff] This
species is sometimes confused with C. acuminatus (scales of spikelets 3-nerved, with pointed
but not awn-like tips) but can be distinguished by its spikelet scales having 5–11 nerves with
long acuminate, awn-like tips. A similar species, Cyperus cuspidatus Kunth (with a sharp stiff
point or cusp), COASTAL-PLAIN FLAT SEDGE, a minute annual to only 5(–9) cm tall with the scales
of the spikelets strongly recurved at tip (and thus similar to C. squarrosus), is cited for TX by
Tucker (1994) and by Kartesz (1999) for SC s to FL w to TX. However, Tucker et al. (2002), did
not include TX within the range of this species. While we have no definitive evidence that this
taxon is a member of the East TX flora, it is mentioned here as a note to encourage collectors to
look for it. It can be distinguished from C. squarrosus as follows:
1. Scales of spikelet (0.6–)0.9–1.2 mm long (excluding recurved tip), with the recurved tip extending
abruptly beyond the broad sides of the scale, each side of scales nerveless or with a single
nerve near the midrib; plants without a spice-like odor __________________________________ C. cuspidatus
1. Scales of spikelet (1.2–)1.3–1.8(–2.2) mm long (excluding recurved tip), with the sides of the
scales gradually narrowed to the recurved tip, each side of scales with several distinct nerves;
plants with a persistent spice-like odor _______________________________________________ C. squarrosus
Cyperus strigosus L., (strigose, with straight appressed hairs bent at base), FALSE NUT-GRASS,
STRAW-COLOR FLAT SEDGE. Tufted perennial without rhizomes; culms usually 20–110 cm tall,
with base swollen, corm-like; spikelets usually pinnately arranged in often rather loose elongate
spikes, the spike axis visible; achenes (1.5–)1.8–2.4 mm long. Low sandy soils; widespread
in e 2/3 of TX, scattered to the w; s Canada and nearly throughout the U.S. Jun–Oct. [C. hansenii
Britton, C. stenolepis Torr., C. strigosus var. hansenii (Britton) Kük., C. strigosus var. stenolepis
(Torr.) Kük.] Two other common species, C. odoratus and C. erythrorhizos can be distinguished
from C. strigosus as follows: C. erythrorhizos has spikelet scales much smaller (1.2–1.5 mm long)
than those of C. odoratus (usually 2.2–2.8 mm long) or C. strigosus (usually 3.2–5 mm long). In
addition, C. strigosus has flattened spikelets, while those of C. odoratus are subcylindric (Tucker
et al. 2002). m/284
Cyperus surinamensis Rottb., (of Surinam), TROPICAL FLAT SEDGE. Tufted perennial, short-lived,
flowering first year, (10–)30–60(–80) cm tall; culms rough to the touch, with minute retrorse (=
down-pointing) teeth; inflorescences with spikelets digitately arranged in crowded head-like
clusters; achenes 0.7–0.9 mm long. Low moist areas; widespread in e 1/2 of TX; mainly se U.S.
from SC s to FL w to OK and TX, also KS. Jul–Nov. This is the only East TX species with retrorse
teeth on the culms and inflorescence rays (= main branches). Lipscomb (1978) discussed the
range of this species.
Cyperus thyrsiflorus Jungh., (with bunch-like inflorescence), SOUTHERN FLAT SEDGE. Rhizomatous
perennial usually 40 cm or less tall; inflorescences with spikelets in spikes, the spikes
loose enough that the inflorescence axis is easily visible when pressed and dried; achenes 1.8–2.1
mm long. Wooded areas; Anderson, Colorado, Fayette, Harris (Turner et al. 2003), and Liberty
(Brown et al. 2002a) cos.; also Gulf Prairies and Marshes and South TX Plains; se U.S. from GA s
to FL w to TX. May–Sep. [C. dissitiflorus Nees ex Torr.]
Cyperus virens Michx., (green), GREEN FLAT SEDGE. Tufted perennial (16–)60–100 cm tall; culms
sharply 3-angled, scabrous on angles only; leaf blades, leaf sheaths, and bracts with knot-like