f 



1 1 1 



-h -f Spikes more or less apiciilate, Avings narrowly ovate or 



elliptical. 



jl |[ lirai^s decfdiiuus. 

 /^^ Lea\-es acicular, hracTs pi-rsistent. 

 C Spikt-s cyliutjrical. 



^ Leaves sn-iall. 2"-6" lon^, ublanceolatc tu liricar, 21. P. Xuttallii 



18. V. Curli:5sii. 



19. P. Mariana. 

 20. P. Chapinanii. 



ri 



/\/\ Leaves ktuceolate. 

 D G C ZL I^l'ikes coiiicaL 

 Iff Fk)\vers i]i ract-ines. 



22. V. Senega 



23. P. alba. 



J Leaves subulate-linear. 



* -Nk^iture capsule obscurely half-winded, or win^lrss. 



** 



24. P, scoparla. 

 Mature capsule distinctly lialf-\\'ini;ed. 25. P. bemipterocarpa. 



;*;;*; Leaves oblanceolate to oblon<>-. 

 Ittt Flowers large. 1.4. axillary, but apparently 



26. P. polyoma. 



terminating the stem. 



27. P. paucitolia 



§ 2. Keel witlt no proper crest, but furnished with a solitary, beak-like process 

 t Flowers 2" -3" lono'. 



t Ik'alc slender, ahnost filiform, abmit 14" Ion 



* Lea\'es oval to lanceolate. 

 ** Leaves linear lance«)lalt' to linear. 



*!■ 



28. P. JJndlifimeri. 



If 



29, P. Tweedyi. 



"I'l Beak short, conical, blunt, or r^•presented by a mere ridge; 



brai^clies spinose. 



tt Flowers 4" ^6" Ion jr. 

 J Beak blunt. 



* Branches often .spinose. 



** Branches spineless. 

 4^ Leaves canescent. 

 4^4t^ Leaves glabrous or pubcrulent. 

 X'l P»eak acicular. 



30. P. acanthi>clada. 



31. P. subspinosa. 



32. P. Ru:>byi. 



33. P. Californica. 



34. P, cornuta. 



3. Keel without crest or beak. 



f Flowers solitary, scatterrd 

 ft Flowers in racemes. 



5. P. macradenia 



J Leaves broadly ovate to ovate-lanceolate. 36. P. ovatifoiia. 



XX Leavt^s linear lanceolate to lancetMale. 



* Wings obovate; styU- curved. 



37. P. puberula. 



*' Win^s circular-deltoid; style bent at an acute angle. 



38. P, grandlflora 



