1 | Female spikes pendulous, green, cylindrical, up to 18 cm long; plant very robust |
1' | Female spikes either absent or not pendulous, much less than 18 cm long |
2 | Spikes ovoid or rounded with male flowers at the top and female flower below (androgynous); stigmas 2 |
2' | Spikes either all male or all female (occasionally the uppermost female partly male at the top); stigmas 3 |
3 | Plants with a long, creeping rhizome and dense, brown inflorescence |
3' | Plants tufted |
4 | Inflorescence dense, lower spikes approximate, often branched, soon becoming brown; culms more than 3 mm wide at base, very sharply trigonous; ligule longer than 3 mm |
4' | Inflorescence interrupted, lower spikes more or less distant, sometimes approximate, green except when old; culms 2-3 mm wide at base, obtusely trigonous; ligule up to 3 mm long |
5 | Inflorescence with 0-2 basal spikes compound; utricles longer than 4 mm; beak 1.0-1.75 mm long, its apical teeth 0.6-1.0 mm long |
5' | Inflorescence with 3-4 basal spikes compound; utricles 3.0-3.5 mm long; beak 0.7-1.0 mm long, its apical teeth 0.2-0.5 mm long |
6 | Inflorescence short, of one terminal male spike and one female below; small tufted plants; utricle clearly ribbed, inflated-trigonous, scrabridulous-pubescent |
6' | Inflorescence of more than 2 spikes; utricle not both clearly ribbed and scabridulous-pubescent |
7 | Female spikes very few-flowered (flowers 1-6); utricles substipitate |
7' | Female spikes many-flowered; utricles not stipitate |
8 | Utricles beakless, somewhat inflated |
8' | Utricles with a more or less pronounced, bifid beak |
9 | Male spikes 3-4; utricle hispid-scabridulous, not ribbed |
9' | Male spikes 1-2; utricle glabrous |
10 | Leaves narrow, inrolled; female spikes approximate; utricle nervose-ribbed |
10' | Leaves flat; female spikes remote |
11 | Male spikes fulvous or purplish-brown, up to 50 mm long; female spikes 10-30(-50) mm long; culms up to 90 cm long |
11' | Male spikes dark purple, up to 18 mm long; female spikes 5-15 mm long; culms rarely exceeding 25 cm |