THE GENUS CAREX IN CALIFORNIA 11 



Lowest bract sheathless or long-sheathing; if long-sheathing its blade well-developed. 

 Lowest bract strongly sheathing; perigynia never strongly bidentate with stiff teeth. 



Achenes lenticular; stigmas two 20. Bicolores. 



Achenes triangular; stigmas three. 



Scales greenish or light reddish-brown or purplish tinged. 



Rootstocks long-creeping; scales purplish tinged 21. Panicem. 



Rootstocks not long-creeping; scales greenish to reddish-brown tinged. 

 Perigynia glabrous or hispidulous; leaves not pubescent. 



Pistillate spikes erect on stiff peduncles 22. Laxiflorm. 



Pistillate spikes slender on slender peduncles, the lower droop- 

 ing 24. Debiles. 



Perigynia or leaves or both strongly pubescent 23. Triquetrce. 



Scales dark reddish-brown to blackish tinged 25. Frigidw. 



Lowest bract sheathless or sheathing; if sheathing, perigynia strongly bidentate 

 with stiff teeth. 



Perigynia or leaves or both pubescent 31. Hirtm. 



Neither perigynia nor leaves pubescent. 



Style jointed with the achene, deciduous. 

 Achenes triangular; stigmas three. 



Lowest bract sheathless; perigynia not bidentate. 



Pistillate spikes narrowly cylindric, elongated. 26. Anomalce. 



Pistillate spikes ovoid, oblong or linear 27. Atratm. 



Lowest bract sheathing; perigynia bidentate 32. Extensa. 



Achenes lenticular; stigmas two. 



Achenes not constricted in the middle 28. Acutw. 



Achenes constricted in the middle; scales sharp-pointed, three- 

 nerved 29. Cryptocarpce. 



Style persistent, continuous with the achene. 



Perigynia nerveless, except for the marginal nerves.. .30. Trachychlmnce. 

 Perigynia several-many-nerved. 



Perigynia coarsely ribbed 33. Physocarpce. 



Perigynia finely and closely ribbed 34. Pseudo-cyperew. 



1. In flat ae. 



Scales 1-nerved; perigynia ovoid, inflated, tapering at apex; staminate part of spike scarcely con- 

 spicuous; achenes 1.25 mm. long 1. C. Engelmannii . 



Scales 3-nerved; perigynia broadly ovoid, strongly inflated, very abruptly short-beaked; staminate 

 part of spike conspicuous; achenes 2 mm. long 2. C. Breweri. 



2. Athrochlaenae. 



Represented by one species in our range 3. C .nigricans. 



3. Capitatse. 

 Represented by one species 4. C. capitata. 



4. Fcetidas. 



Represented by one species in our range 5. C. vernacula. 



5. Divisae. 



Rootstocks slender, light brownish; culms obtusely triangular, normally smooth; leaf-blades narrow, 



involute 6. C. Douglasii. 



Rootstocks stout; culms acutely triangular, normally rough above. 



Perigynia chestnut, thick, the beak about one-fifth as long as the body 7. C. simulala. 



Perigynia blackish in age, the beak one-third to one-half as long as the body. 



Scales very dark chestnut-brown, shining; perigynia 3.5-4.5 mm. long, polished, scarcely 



hyaline at orifice 8. C. pansa. 



Scales lighter colored, dull; perigynia 3-4 mm. long, dull, strongly hyaline at orifice 



9. C. prccgracilis. 



6. Muhlenbergianae. 



Densely cespitose; head orbicular or oblong-ovoid 10. C. Hoodii. 



Rootstocks elongate; head linear, interrupted 11. C. tumulicola. 



