I. Leaves pinnate or entire; inflorescence with fruits lacking scales. 



2. Liana; pinnae in the upper portion of the leaf modified into retrorse 



spines; leaf sheaths spiny 2. Desmoncus sp. 



2. Erect trees or shrubs; pinnae in the upper portion of the leaf not 



modified into spines; leaf sheaths spiny or smooth. 



3. Trunk and leaf sheaths spiny at maturity, or if plant acaulescent, 



petiole and rachis covered with spines. 



4. Trunk diameter 1-2.5 cm; lower surface of pinnae green. . . , 



3. Bactris aff. maraja 



4. Trunk diameter 4-5 cm or lacking entirely; lower surface of 

 pinnae silver or scurfy-whitish. 

 5. Leaves to 2.25 m long, with pinnae regularly arranged 



along the rachis; trunk developed 



4. Astrocaryum aff. munbaca 



5. Leaves to 5 m long, with pinnae irregularly arranged 

 along the rachis in separated groups of 2-3(4); trunk 



not developed 5. Astrocaryum acaule 



3. Trunk and leaf sheaths smooth at maturity. 



6. Stilt roots present, these containing spines 



6. Socratea exorrhiza 



6. Stilt roots absent, trunk firmly inserted into the ground. 



7. Inflorescence a hippuriform panicle, shaped like horse's 

 tail. 

 8. Underside of pinnae covered with sickle-shaped tri- 



chomes 7. Jessenia bataua 



8. Underside of leaves without trichomes, often with 

 a waxy bloom that wears away with age. 

 9. Trunk solitary; leaves ca 4.25 m long, pinnae 80- 

 90 per side; rachis 0.7- 1 .0 m long 



8. Oenocarpus bacaba 



9. Trunks solitary to few and clustered; leaves ca 

 2.25 m long, pinnae 55-60 per side; rachis 



0.4-0.5 m long 9. Oenocarpus mapora 



7. Inflorescence not a hippuriform panicle. 

 10. Pinnae clustered. 



1 1 . Inflorescences differentiated into two kinds on 

 the same plants, one androgynous with pistil- 

 late and staminate flowers at the base of the 

 rachis but only pistillate distally, and the 

 other entirely staminate; trunk greater than 



15 cm in diameter 



10. Maximiliana maripa 



1 1. Inflorescences of one kind on any plant, each 

 containing staminate and pistillate flowers; trunk 

 no greater than 10 cm in diameter 



11. Syagrus inajai 



10. Pinnae regularly arranged or undivided laterally. 

 12. Tall palm with many regularly inserted, pen- 

 dulous, one-ribbed pinnae 



12. Euterpe precatoria 



4 



