22 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[vol. 10 



Key to the Genera of Rapateaceae 



1. Carpels pluriovulate ; placenta axial or sometimes also on the partitions; seed more 

 or less prismatic or pyramidal, neither oval nor oblong (Saxofriclericioideae). 

 2. Corollas yellow; petals obcordate or obovate, conspicuously exserted (Saxofrid- 



ericieae ) . 



3. Inflorescence bibracteate (pluribracteate in Saxofridericia regalis), bivalvate; 

 scapes commonly solitary, sometimes 2. 

 4. Anthers 4-celled, apically appendaged, dehiscing by a single subapical pore; 

 heads massive, subglobose or hemispheric; coarse perennial herbs 1.5 m or 

 more high; scapes terte or compressed. 1. Saxofridericia. 



4. Anthers 2-celled, exappendiculate, dehiscing by 2 circular apical pores; heads 



small, strongly compressed; perennial herbs 0.5 m or less high; scapes 

 strongly compressed, broadly winged. 2. Fhelpsiella. 



3. Inflorescence tri- or pluribracteate, the 2 outer bracts valvate, keeled, connate, 

 the inner enclosed; scapes solitary or few; leaves narrowly linear, 8-10 mm 

 broad, involute. 3. Amphiphyllum. 



3. Inflorescence ebracteate, or the bracts represented by a short scale-like mem 

 brane; scapes several or numerous, rarely only 1. 



5. Anthers strongly transversely rugose; 4-celled; seed pyramidal; endocarp not 



separating from the exocarp; terrestrial. 4. Stegolepis. 



5. Anthers smooth, not at all rugose, 1 -celled; seed disciform; endocarp indurate, 



separating from the exocarp; epiphytic. 5. Epiphyton. 



2. Corollas and/or spikelets red or reddish ; petals narrowly lanceolate, included within 

 the indurated sepals, except for Kunhardtia (Schoe?iocephalieae) . 

 6. Corollas conspicuously exserted, porrectate ; heads depressed-subglobose ; anthers 



2-celled; leaf-blades exceeding 3 cm in width. 6. Kunhardtia. 



6. Corollas included within the sepals; heads spheroidal, the flowers radiate at ma- 

 turity; anthers 4-celled, at least towards the base; leaf -blades less than 3 cm 

 in width. 



7. Apex of the anthers bilobed, dehiscing by 2 apical pores ; heads relatively mas- 

 sive ; cephalar bracts ruptured by the expanding inflorescence, not reflexed ; 

 union of leaf -blade and sheath transversely abrupt. 7. Guacamaya. 



7. Apex of the anthers cruciform, dehiscing by 4 apical pores, the lateral often 



at length confluent; heads spherical, smaller; cephalar bracts reflexed; union , 

 of leaf -blade and sheath reciprocally obliquely attenuate. 8. Schoenocephaliv/m. 



1. Carpels uniovulate ; placentation basal or axially subbasal ; seed oval or oblong 



(Rapateoideae). 



8. Seed oval-oblong or oblong, longitudinally striate, devoid of an apical appendage, 

 or the appendage papillate-mitrif orm ; involucral bracts conspicuously surpassing 

 the inflorescence (Rapateeae) . 

 9. Involucral bracts 2, bivalvate; ovary perfectly 3-celled. 



10. Anthers cochleariform-appendaged ; seed exappendiculate; leaves nongrami- 



neous. 9. Bapatea. 



10. Anthers exappendiculate: leaves gramineous. 



11. Seed with a conspicuous papillate-mitrif orm appendage. 10. Cephalostemon. 



11. Seed exappendiculate. 11. Duckea. 



9. Involucral bract solitary, spathaceous, laterally adnate to the elongate spicate 

 inflorescence; ovary imperfectly 3-celled, only a solitary cell developing. 



12. Spathanthus. 



8. Seed oval to subglobose, more or less conspicuously white-granulate, not striate, 

 apically applanate-appendaged ; involucral bracts equaling or shorter than the 

 mature inflorescence (Monotremeae) . 

 12. Inflorescences long-pedunculate, much exceeding the leaf -sheaths. 



13. Spikelets sessile, the inflorescence capitate; anthers 4-celled, dehiscing by an 

 apical pore. 



14. Inflorescence bibracteate, bivalvate; anther-pore obliquely terminal ; cap- 

 sule retuse; leaves more or less gramineous. 13. Monotrema. 



14. Inflorescence quadribracteate, the bracts decussate; anther-pore trans- 

 versely terminal ; capsule deeply emarginate ; leaves broadly linear, not 

 gramineous. 14. Potarophytum. 



