162 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



cane chair seats, etc. The bases of the stalks of one species (S. 

 acutus?) are eaten raw by the Hopi Indians. 



The writers are indebted to Alan A. Beetle (personal communica- 

 tion) for the characterizations of the first two species. 



Key to the species 



1. Stems terete or nearly so, tall and stout, leafless except near base, the stem 



leaves mostly reduced to sheathing scales; primary inflorescence subtended 

 by 1 or 2 bracts; spikelets several or numerous; bristles 4 to 6, slender, 

 terete or nearly so, retrorsely barbed (2). 



2. Roots fibrous; spikelets ovoid, acutish; scales little longer than the mature 



achenes 1. S. validus. 



2. Roots swollen, spongy; spikelets subcylindric; scales considerably longer than 



the mature achenes 2. S. acutus. 



1. Stems triangular (3). 



3. Inflorescence a once- or twice-compound panicle of umbels with numerous 

 unequal rays; spikelets usually numerous (many more than 10), seldom 

 more than 6 mm. long, greenish or blackish (4). 

 4. Achene plano-convex; style branches 2; inflorescence usually twice com- 

 pound; spikelets commonly in loose clusters 6. S. MICROCARPUS. 



4. Achene triangular; style branches 3; inflorescence usually once com- 



pound; spikelets commonly in dense clusters 7. S. pallidus. 



3. Inflorescence a single head or compact umbel; spikelets few (seldom more 

 than 10), usually 10 mm. long or longer, brown or yellowish (5). 



5. Involucral bracts 2 or more, leaflike, flat; leaves equaling or surpassing 



the stems; inflorescence appearing terminal; spikelets straw-colored or 



pale brown, up to 25 mm. long 3. S. paludosus. 



5. Involucral bract solitary, appearing like a prolongation of the stem; 

 leaves usually much shorter than the stems; inflorescence appearing 

 lateral; spikelets seldom more than 15 mm. long (6). 

 6. Stems slender, wiry; leaves commonly half or more as long as the stems; 

 spikelets very few (commonly not more than 4), frequently solitary; 

 involucral bract commonly 4 cm. long or longer; scales long-cuspi- 

 date or aristate 4. S. americanus. 



6. Stems stout, not wiry; leaves much less than half as long as the stem; 

 spikelets usually 4 or more; involucral bract commonly less than 

 4 cm. long; scales mucronate or short-cuspidate 5. S. olneyi. 



1. Scirpus validus Vahl, Enum. PL 2: 268. 1806. 



Coconino, Yavapai, Gila, Pinal, and Cochise Counties, up to 5,000 

 feet. Almost throughout the United States and Canada. 



The largest of the Arizona species, the stems reaching a height of 

 2.4 m. (8 feet) or more. 



2. Scirpus acutus Muhl. ex BigeL, Fl. Bost. 15. 1814. 



Scirpus occidentalis (S. Wats.) Chase, Khodora 6: 68. 1904. 



Apache, Navajo, and Coconino Counties, south to Cochise and Pima 

 Counties, 2,300 to 9,000 feet. Widely distributed in Canada and the 

 United States. 



Very similar to S. validus, with which this species apparently inter- 

 grades in Arizona. Both species are known in California as "tule." 

 According to E. Palmer (MS.) the Indians of Arizona used the roots 

 of this or a related species as food. 



3. Scirpus paludosus A. Nels., Torrey Bot. Club Bui. 26: 5. 1899. 



Scirpus campestris Britton in Britton and Brown, Illus. Fl. 

 1:267. 1896. Not Roth, 1795. 



Apache and Navajo Counties to Pinal and Maricopa Counties, 

 1,000 to 5,000 feet. Quebec to British Columbia southward to New 

 Jersey, Arizona, and California. 





