70 FLOBA OF PHILADELPHIA. 



Perigynia with a straight, short beak (long-beaked in No. 26; 

 nearly beakless in No. 21), firm or leathery in texture; 



pistillate spikes erect; stigmas 3. , 

 Uppermost spike starninate from the base ' to about the 



middle. 6. Shortianae. 



Uppermost -spike entirely starninate, or occasionally pistil- 

 late at the base. 

 Perigynia papillose; beak very short, nearly or quite 



entire. ' 7. Anomalae. 



Perigynia pubescent.; beak sharply 2-toothed. 



8. Hirtae. 

 Perigynia beakless or very short-beaked (see No. 21), and with 



orifices nearly or quite entire, thin in texture, not in- 

 flated, closely investing the achene ; pistillate spikes 

 erect or drooping, often brown or purple; stigmas 

 often 2. 

 Pistillate spikes erect or somewhat spreading. 

 Terminal spike starninate below; stigmas 3. 



9. Atratae. 

 Terminal spike starninate throughout; stigmas 2. 



10. Bigidae. 

 Pistillate spikes drooping, mostly on slender peduncles. 

 Pistillate spikes 0.6-7.5 cm. long; stigmas 3 (2 in 

 No. 32). 

 Pistillate spikes linear; scales shorter than the 



perigynia. 11. Prasinae. 



Pistillate spikes globose, oblong or cylindric; 

 scales as long as the perigynia, or longer. 

 12. Pendulinae. 

 Pistillate spikes 2.5-10 cm. long; scales 1-8 times as 

 long as the perigynia. 13. Gryptocarpae. 



Perigynia tapering to a distinct beak (nearly or quite beakless 

 in Nos. 38-42), membranous in texture (firm in No. 48), 

 inflated or loosely investing the achene; pistillate spikes 

 mostly drooping, often narrowly linear. 

 Terminal spike starninate below, pistillate above; peri- 

 gynia short-beaked or beakless. 

 Spikes all erect or nearly so. 14. Virescentes. 

 Pistillate spikes drooping or spreading (erect or 

 little spreading in No. 43). 15. Grac&limae. 

 . Terminal spike wholly starninate, or sometimes pistillate 

 at the base. 

 Perigynia manifestly beaked, nerved or nerveless; 

 pistillate spikes drooping. 

 Beak of the perigynium cylindric or subulate, 

 once or twice as long as the body. 



16. Sylvatioae. 

 Beak of the perigynium not more than as long 

 as the body. 17. Debiles. 



Perigynia beakless or minutely beaked, finely many- 

 striate; spikes erect or nearly so. 



18. Griseae. 

 Pistillate spikes small, few-many-flowered, mostly 6-25 mm. long 



(sometimes longer in No. 58). (See also Nos. 27, 38, 40, 

 41, 44, 49-51). ' 



Perigynia glabrous. 



Pistillate spikes many-flowered, 6-25 mm. long, usually 

 . " • dense. 



Pistillate spikes scattered, distant, long-stalked, or 

 the two upper ones approximate and nearly sessile. 



19. Granulares. 

 Pistillate spikes approximate and nearly sessile at the 



