40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 26 



12. Petal-scales vestigial; sepals definitely asymmetric, 25-35 mm- 



long; inflorescence or its spikes many-flowered, 6-15 cm. in 



diameter 29. Aechmea 



II. Scape-bracts distinct from the leaves, or if there is no evident scape 

 (some species of Aechmea) then the sepals much connate; epigy- 

 nous tube often large. 



13. Inflorescence involucrate; sepals unarmed, nearly or quite free 



in most species. 

 14. Petals completely free. (Figs. 86, 87.) 25. Canistrum 



14. Petals partially connate above the base but often free at the base 



and exposing the bases of the filaments of the first series. 



(Figs. 88-90.) 26. Wittrockia 



13. Inflorescence not involucrate or if somewhat so then the sepals 

 mucronate and much connate. 



15. The inflorescence compound (simple in depauperate specimens 



of Hohcnbergia littoralis) ; flowers in strobilate spikes, much 

 compressed. 

 16. Epigynous tube very small or lacking ; pollen-grains with 2 or 

 4 pores. (Figs. 91-93.) 27. Hohenbergia 



16. Epigynous tube well developed ; pollen-grains with more than 



4 pores. (Fig. 94.) 28. Gravisia 



15. The inflorescence simple or if compound then the flowers not in 

 strobilate spikes. 



17. Flowers sessile or if rarely pedicellate then the sepals free. 



18. Sepals mucronate or pungent or if blunt then small and the 



ovules long-caudate. (Figs. 95-111.) 29. Aechmea 



18. Sepals unarmed or soft-apiculate. 

 19. Ovules numerous. 

 20. Petals regular, erect or suberect; pollen-grains with 

 pores; flowers sessile. (Figs. 112-114.) 



30. Quesnelia 

 20. Petals either zygomorphic or recurved in a spiral ; dry 



pollen-grains usually with a single longitudinal fold; 

 flowers sessile or pedicellate. (Figs. 115-123.) 



31. Billbergia 

 19. Ovules few; flowers pedicellate, regular. (Fig. 124.) 



32. Neoglaziovia 

 17. Flowers pedicellate; sepals connate; pollen-grains with more 



than 4 pores. (Fig. 125.) 33. Portea 



9. Ovaries fused with each other and with the fleshy bracts to form a syncarp ; 

 inflorescence with an apical coma, simple; sepals never mucronate. 

 21. Inflorescence with a small inconspicuous coma, never producing basal 

 shoots ; plant propagating by elongate rhizomes ; petals bearing 



vertical folds. (Fig. 126.) 34- Pseudananas 



21. Inflorescence with a large conspicuous coma, often with basal shoots; 

 rhizomes lacking; petals usually bearing well developed scales (Figs. 

 127, 128.) 35. Ananas 



