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

518 CYPERACEAE/CAREX
9. Leaf sheaths baggy (loose) around the culm _________________________________ C. gravida
9. Leaf sheaths tight (not loose) around the culm.
10. Lowest inflorescence bract 5.5–25 cm long, greatly exceeding the inflorescence,
two to many times as long as the inflorescence.
11. Culms smooth below inflorescence; plants of open or semi-open bottomlands
or floodplain habitats _____________________________________ C. arkansana
11. Culms antrorsely scaberulous below inflorescence; plants of open mesic
to submesic woodlands ________________________________________ C. perdentata
10. Lowest inflorescence bract less than 5.5 cm long, not exceeding the inflorescence,
or less than two times as long as the inflorescence.
12. Beaks of perigynia smooth, not serrated.
13. Perigynia ovate-deltoid, veinless ventrally, spongy at base but without
a swollen spongy area at base on ventral surface ______________ C. leavenworthii
13. Perigynia ovate-lanceoid, with veins present or absent on ventral surface,
with an enlarged spongy area at base of perigynia.
14. Perigynia 1.3–1.8 mm wide; widest leaf blade 1.5–3 mm wide; veins
present on ventral surface over enlarged spongy area at base of
perigynia. ______________________________________________ C. retroflexa
14. Perigynia 1–1.3 mm wide; widest leaf blade 1–1.5 mm wide; veins
absent on ventral surface over enlarged spongy area at base of
perigynia _______________________________________________ C. texensis
12. Beaks of perigynia serrated, not smooth.
15. Perigynia spongy at base (especially ventrally), with or without a swollen
area at base.
16. Perigynia (1.4–)1.5–2.7(–2.8) mm wide, ovate-deltoid or conspicuously
ovate, without a swollen spongy area at base on ventral surface.
17. Perigynia 2.2–3.2(–3.3) mm long, veinless ventrally, with 0(–3)
veins dorsally ____________________________________ C. leavenworthii
17. Perigynia (3.3–)3.4–5.2(–5.6) mm long, with 0–5(–8) narrow
veins (ca. 0.1–0.2 mm wide) ventrally, with 0–10(–11) narrow
veins dorsally _______________________________________ C. perdentata
16. Perigynia 0.9–1.8 mm wide, ovate-lanceoid or slightly ovate-oblong,
with a swollen spongy area at base of ventral surface.
18. Perigynia (3–)4–5 times as long as wide, 3.6–4.1 mm long, 0.7–
1.2 mm wide; plants with ± elongate rhizomes _______________ C. socialis
18. Perigynia 3 or less times as long as wide, 3–3.5 mm long, 1.4–
1.6 mm wide; plants without elongate rhizomes ________________ C. rosea
15. Perigynia not spongy at base.
19. Adaxial and abaxial leaf surfaces smooth, not minutely papillose
(sandpaper-like), except sometimes sparingly so along major veins.
20. Perigynia (3.4–)3.5–4.7 mm long, (2–)2.1–2.7(–3.1) mm wide.
21. Apex of the ventral surface of leaf sheath straight or
slightly concave, not callused or only slightly thickened,
friable (= easily crumbled); frequently with scattered reddish
dots; dorsal surface of leaf sheaths white or pale green
with darker green longitudinal veins, with darker green
septate-nodules, but not green mottled with white; widest
leaf blade (3–)4–8 mm wide; most culms forming
greater than 70° angle with the ground _________________ C. gravida
21. Apex of ventral surface of leaf sheath concave, callused,
not friable; without scattered reddish dots; dorsal surface