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

CAREX/CYPERACEAE
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The following key to species is based on mature perigynia (= sac-like structure enclosing the
pistillate flower and later the fruit) and fruits (achene); fruiting material is essential for proper
identification. The following specialized terminology may be helpful: infructescence = a mature
inflorescence, in other words, an inflorescence in fruit; incomplete veins = veins that do not extend
the entire length of the perigynium body; septate-nodulose = with conspicuous cross venation;
androgynous = condition where the staminate flowers are distal to the pistillate flowers;
gynecandrous = condition where the pistillate flowers are distal to the staminate flowers;
abaxial side = side away from the axis or dorsal side; adaxial side = side toward the axis or ventral
side. Digital images (line drawings) of most East TX Carex species are available on-line
(TAMU 1997). (The classical Latin name, of obscure origin; possibly from the Greek: keirein, to
cut, on account of the sharp leaves—as indicated in the English name SHEAR-GRASS)
REFERENCES: Kükenthal 1909; Mackenzie 1931—35, 1940; Hermann 1954, 1970; Bryson 1980;
Reznicek & Ball 1980; Menapace et al. 1986; Tucker 1987; Standley 1989, 1990, 2002a, 2002b,
2002c; Ball 1990; Bernard 1990; Crins 1990; Jones & Hatch 1990; Manhart 1990; Naczi 1990, 1992,
2000, 2002; Naczi & Bryson 1990; Reznicek 1990, 2002a, 2002b, 2002c; Jones & Reznicek 1991,
1995; Jones et al. 1991a, 1991b; Rothrock 1991; Cayouette & Catling 1992; Jones & Jones 1993;
Reznicek & Naczi 1993; Jones 1994a, 1994b; Rothrock & Reznicek 1996a, 1996b, 2001, 2002;
Ford et al. 1998; Hyatt 1998; Naczi et al. 1998, 2002; Miller et al. 1999; Mohlenbrock 1999; Starr et
al. 1999; Yen & Olmstead 2000a, 2000b; Roalson et al. 2001; Rosen 2001; Ball 2002a, 2002b,
2002c; Ball & Reznicek 2002; Bryson & Naczi 2002a, 2002b; Cochrane 2002a, 2002b;
Cochrane & Naczi 2002; Crins & Rettig 2002; Crins et al. 2002; Ford & Reznicek 2002;
Mastrogiuseppe et al. 2002; Naczi & Bryson 2002; Reznicek & Catling 2002; Reznicek & Ford
2002; Standley et al. 2002; Waterway 2002; Downer & Hyatt 2003; MacRoberts et al. 2004;
Starr et al. 2004.
1. Achenes 2–sided, plano-convex or unequally biconvex in transverse-section; stigmas 2.
2. Infructescence (= inflorescence in fruit) 2–5 cm wide, usually an open or contracted panicle
of spicate branches.
3. Perigynia with beak as long as or longer than the body; dorsal surface of leaf sheaths green
without white dots; ventral leaf sheath margins with orange-red dots; achenes ovate-
3. Perigynia with beak shorter than the body; dorsal surface of leaf sheath dark blue-green
with conspicuous white dots; ventral leaf sheath margins without orange-red dots; achenes
broadly ovate; perigynial wall little to not at all adhering to achene ________________ C. oklahomensis
2. Infructescence less than 1.5 cm wide, a contracted panicle of spicate branches, spicate racemes,
or composed of terminal, lateral, or terminal and lateral spikes.
4. Terminal spike solely staminate, or sometimes partly pistillate as in some specimens of C.
crinita.
5. Lateral spikes conspicuously peduncled, drooping or not _______________ C. crinita var. brevicrinis
5. Lateral spikes, at least the lower, sessile or nearly so, ascending.
6. At maturity leaf sheaths becoming fimbriate filiferous, hyaline material between veins
fugacious, leaving only a reticulate network of veins; lower lateral spikes usually remote;
perigynia granular-papillate in upper half __________________________________ C. stricta
6. At maturity leaf sheath not becoming fimbriate filiferous, hyaline material between
veins not fugacious, not leaving a reticulate network of veins, instead leaving leaf
sheath intact; lower lateral spikes overlapping; perigynia granular-papillate only
apically _________________________________________________________________ C. emoryi
4. Terminal spike either androgynous or gynecandrous.
7. Terminal or all spikes androgynous (in some species the staminate flowers often fugacious,
making spikes appear solely pistillate); spikes not appearing clavate.
8. Primary spicate branches usually less than 10, most frequently the primary branches
comprised of a single spike, infrequently rebranching giving rise to secondary spikes.