CYPERACEAE 19 
6. Scirpus. 174, 
Involucre of a single bract or wanting. 
Spikelets few, 1 to 7, appearing lateral. 
Culms terete, bristles none, annuals. 1. S, hallii. 
Culms sharply triangular, bristles 2-4, perennials with rootstocks. 
2, S. americanus. 
Spikelets numerous, umbellate. 
Achene lenticular. 
Achene 2 mm. long nearly equalling the scale., 3. S. validus. 
Achene 2.5-3 mm. long much exceeded by the scale. 
4. S. occidentalis. 
Achene triangular, bristles unequal, shorter than achenes. 
5. S. heterochaetus, 
Involucre of two or more leaves, 
Spikelets large, 1-5 cm. long, 5-10 mm. thick. 
Achene lenticular, spikelets capitate. 6. S. interior. 
Achenes sharply triangular, spikelets umbellate. 7. S. fluviatilis. 
Spikelets small, 2-15 mm. long, 1-3 thick. 
Scales dark brown, one-third longer than the achene. 
8, S. atrovirens. 
Scales light brown, twice as long as the achene. 9. S. pallidus. 
1. Scirpus hallii Gray. 
Not common. Holt County; Kennedy. 
2. Scirpus americanus Pers. 
Common in the western parts of the state. Anselmo; Aten: Broken 
Bow; Franklin; Hackberry Springs in Banner County; Hat Creek 
Basin; Louisville; Red Cloud; Thedford. 
3. Scirpus validus Vahl. Great Bulrush. 
Scirpus lacustris L. 
Common in marshes. Broken Bow; Cherry County; Lincoln; Nebras- 
ka City; Newcastle; Scotts Bluff County; Thedford; Wahoo; Valen- 
tine. ; 
4. Scirpus occidentalis (Wats.) Chase. 
Kearney; Thedford. 
5. Scirpus heterochaetus Chase. 
Nebraska, according to Britton’s Manual. 
6. Scirpus interior Britton. 
Scirpus campestris Britton. 
Alliance; Kearney County; in Lone Tree Lake near Kennedy; Laurel; 
Lincoln; Newark; St. James; Whitman. 
7. Scirpus fluviatilis (Torr.) A, Gray. - River Bulrush. 
In wet, marshy places oyer most of the state. Kennedy; Merriman. 
-8. Scirpus atrovirens Muhl. ' 
Common in wet places. Beatrice; Lincoln; Minden; Nehawka; St. 
James; Weeping Water. 
9. Scirpus pallidus (Britton) Fernald. 
Scirpus atrovirens var. pallidus Britton. 
Common in marshy places, Broken Bow; Crawford; Hitchcock Coun- 
ty; Hooker County; Nebraska City; Talmage; Thedford; Wahoo. 
