no 



§ I. Keel provided with a fimbriate or papillose crest. 



f Flowers in spikes arranged in a corj-mb at the summit of the stem. 

 X Root-leaves lon'T, narrow, acuminate. I. P. cvmosa. 



XX Root-lcaxes spatulate or obo\ ate. 



* Spikes loose, flowers yellow. 





"" Spikes comjxict, Howers white. 



2, V. raniosa. 



3. P. Haldwinii 



ff Flowers in solitary spikes terminating the stem and branches 



X Root-leaves spatuhite or obovate. 



♦ !°-2°high 



** 



6'-r hi-h. 



*** i'-6' hi-h. 



4. ]'. Rugeiii. — Florida. 



5. l\ lutea.^L. I. to Miss. 



6. W nana. — S. C to L. 

 XX Root-leaves inconspicuous or absent. 



* Leaves verticihate. at least tliose below the middle of the stem, 



(except in P. IJoykinii. var. sparsifolia). 



4t= Spikes ovuid, compact. 



o Spikes sessile or nearly so; winj^s deltiMd-acuminate or 



deltoid-ovate. 



7. P. cruciata. 



00 Spikes peduncled; wings lanceolate-ovate. 8. P. brevifolia 



^^ Spikes ovuid-apictdate, loose 

 4t=## spikes conical. 



9. P. Hookeri. 



o Spikes 2" -3" in diameter at base. lower leaves obovate, 



elliptical, lanceolate or lineardanceolate. 10. P. Boykinii. 

 00 Spikes I'^a" in diameter at base, all tlie leaves subulate-linear 



or acicidar. 

 ** Leaves verticillate and alternate 



ii. P. leptostachys 



4|: Verticillate leaves predominating; spikes dense. 12- P. verticillata. 

 4f# Alternate leaves predominating; spikes slender, loose. 13. P. ambigua. 



*** Leaves all alternate. 



=^ Petals united into a conspicuous, slender, cleft tube 3"'4" long. 



14. P. incarnata 



## Petals not united into a conspicuous tube. 



o Leaves reduced to scales. 

 00 Leases never reduced to scales. 



15. P. setacea. 



□ Spikes slender, I "-2" in diameter, often becoming much elongated and 



loose, leaves acicular, bracts deciduous. 



16. P. leptocaulis. 



□ □ Spikes ovoid to globose. 



^ Leaves linear to linear-oblong. 

 II Bracts persistent. 



+ Spikes blunt, wings broadly ovate, imbricated. 



17. P. viridescens- 





^ 



;■ 



