Rhynchospora

KEY TO RHYNCHOSPORA SECT. MIXTAE , MODIFIED FROM MCMILLAN (2006, 2007)

1. AChene body slender ellipsoid-obovoid,more than 1.8 mm long,more than 1.75 times as long as wide ____________ R. inexpansa View in CoL 1. AChene body broader, 1.8 mm or less long,less than 1.75 times as long as wide.

2. AChenes with flat or ConCave faCes,sometimes with one faCe slightly ConCave and the opposite slightly Convex.

3. Perianth bristles longer than the aChene body (1.2–2.1 times as long as aChene body); often exCeeding the

tuberCle and widely spreading;plants robust with widest leaves 2.71–6.21 mm wide __________________________ R. elliottii View in CoL 3. Perianth bristles rudimentary to approximately 0.8 times as long as aChene body, never exCeeding the aChene

body;plants tall but slender,leaves narrower.

4. TuberCle not deCurrent on the aChene body;aChene broadly obovoid to suborbiCular 1.0– 1.4 mm long;surfaCe

with 8 or fewer prominent deep transverse ridges;perianth bristles 1–3 or absent,0.2–0.6 times as long as the

aChene body ________________________________________________________________________________ R. perplexa View in CoL

4. TuberCle deCurrent on the aChene body; aChene obovoid 1.3–1.8 mm long; aChene surfaCe with 10 or more

shallow transverse ridges;perianth bristles 6, 0.4–0.9 times as long as the aChene body ___________________ R. torreyana View in CoL 2. AChenes biConvex,sometimes slightly tumid.

5. TuberCle margins setulose (at least basally), obviously differentiated from the aChene body, not deCurrent, the

base of the tuberCle Clearly differentiated and running straight aCross the summit of the aChene body.

6. AChene narrowly ovoid to obovoid or elliptiC, 0.7–1.2 mm wide,1.0–1.7 times as long as wide; aChene surfaCe

of rows of alveolae without obvious and deep transverse rugosity; tuberCle triangular-subulate, with bases

0.4–0.7 mm wide; plants Cespitose but with long and well-developed rhizomes present but easily broken

during ColleCtion ________________________________________________________________________________ R. mixta View in CoL

6. AChene broadly obovoid to suborbiCular 1.0– 1.5 mm wide,0.9–1.4 times as long as wide; aChene surfaCe evi-

dently and deeply transversely rugulose; tuberCle triangular, broad-based 0.4–0.9 mm wide at base; plants

Cespitose with short or long rhizomes.