A Key to the Sedges of the Valley of Cuatrocienegas, Coahuila, Mexico
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by Jack SiegristNote that this key does not include species that are found only in the surrounding mountains.
1a Leaves absent: 2
2a Spikelets ovoid and few:
3a 1 to 4 large ovoid spikelets at tip; plant to 60cm (2 feet) tall: Fuirena simplex
3b Only 1 ovoid spikelet at tip; plant to 40cm (16 inches) tall:
Eleocharis caribaea
2b Spikelet not ovoid, or if ovoid, there are many spikelets: 4
4a Stems circular, to 120cm (4 feet) tall from rhizomes; single spikelet:
Eleocharis cellulosa
4b Stems compressed near the tips, 40cm to 100cm (16 to 40 inches) tall in tufts;
multiple spikelets: Eleocharis rostellata
1b Leaves present: 5
5a Inflorescence complex and open or bushy: 6
6a Plant 120cm to 300cm (4 to 10 feet) tall: Cladium jamaicense
6b Plant less than 120cm (4 feet) tall: 7
7a Spikelets distributed pinnately on an elongate rachis; annual 4cm to 40cm (1.5 to 16 inches) tall: Cyperus odoratus
7b Inflorescence compound umbels with spikelets on branched tips; plant to 120cm (4 feet) tall: Fimbristylis thermalis
5b Inflorescence simple or compact: 8
8a Inflorescences several long, compact spikes: Carex pringlei
8b Inflorescence not a spike: 9
9a Inflorescence subtended by long, white, leaf-like bracts with green tips:
Dichromena colorata
9b Inflorescence with bracts otherwise: 10
10a Bracts 1 to 2, one to 8cm (3 inches) long: Schoenus nigricans
10b Bracts 3 to 5, one erect to 30cm (12 inches) long; inflorescence 3-20
spikelets: Scirpus maritimus
10c One bract, erect, appearing to be a continuation of the stem, making
the terminal inflorescence of 1-5 spikelets in a single cluster appear to
be in the middle of the stem: Scirpus olneyi