1960] 



TAXONOMIC RELATIONSHIPS OF DIOMMA 



59 



Morphologically, there is good reason to consider subgenus Spathelia the least 

 advanced of the three subgenera (see Stern and Brizicky), and since it is pres- 

 ently restricted to the Bahamas, Cuba, and Jamaica, we may consider this area 

 as the original point from which the genus evolved and migrated southwardly, 

 perhaps by a land-route. Such a view would be strengthened by the presence of 

 some representative of the group in the intervening region (but interconnecting 

 taxa are unnecessary if the dispersal is assumed to be via hurricane winds). A 

 single species from Mexico was referred to the genus by Sesse and Mocino, but 

 Wilson (1911) considers it "a very doubtful species." Unfortunately, the 

 original publication by these authors is so poor that it is difficult to determine 

 the exact affinities of the plant depicted. 



TAXONOMY 



Spathelia Linnaeus, Sp. PI. ed. 2. 386. 1763. (nom. cons.) (emend, et ampl.) 



Spathe P. Browne, Hist. Jam. 187. 1756. (nom. rej.) 



Sohnreyia Krause, Notizbl. Bot. Gart. Mus. Berlin 6: 147-149. 1914. 



Viornma Engler ex Harms, Nat. Pflanzenfam. ed. 2. 19a: 460. 1931. 



Monocarpic trees with palm-like habit, the alternate, pinnate leaves congested 

 at the apex of the unbranched trunk. Leaflets opposite to alternate, 10-100- 

 jugate, the margins crenate to entire, glandular punctae restricted to the margins 

 or generally distributed through the blade. Inflorescences terminal, paniculate, 

 to 3 m long, the flowers polygamous. Sepals 5, free to slightly united basally, 

 valvate to imbricate, the apex with a small to large glandular cavity; petals 5, 

 free, imbricate, the apex with a small to large glandular cavity, rarely the latter 

 not obvious. Stamens 5, the filaments exalate to conspicuously alate, the wing- 

 shortly free at the apex or completely adnate with the filament, bidentate apically 

 or entire. Gynoecium subsessile to stipitate ; stigma 2-3-lobed, sessile or sub- 

 sessile ; ovary 2-3-celled, laterally compressed, the carpels uniovulate, the ovule 

 pendulous, apotropous. Fruit 2-3-winged, indehiscent, the wings narrower to 

 broader than the seed-bearing portion ; seed endospermous or not. 



Type species: 8. simplex Linnaeus, loc. cit. 



Key to the Subgenera 



1. Ovary typically 3-locular, infrequently 2-locular; fruit elliptic to oval, 3 (-2) -winged, 

 each of the wings usually narrower than the seed-bearing portion ; each loeule with a 

 large, dorsal secretory cavity; seeds with a fleshy endosperm. Leaflets rarely entire, 

 up to 100-jugate. Plants of the West Indies. Subg. 1. Spathelia. 



1. Ovary typically 2-locular, rarely 3-locular; fruit ovate to oblate, 2 (-3) -winged, each 



of the wings usually much broader than the seedbearing portion ; locules without a 

 large, dorsal secretory cavity; seeds without endosperm. Leaflets entire, to 27-jugate. 

 Plants of northern South America. 2. 



2. Stigma separated from the ovary by a short style, the lobes capitate or subcapitate; 



gynophore absent or rudimentary; ovary and fruit glabrous within. Secretary cells 

 (microscopic) present in the leaflet tissue. Known only from Guayana. Subg. 2. Diomma. 

 2. Stigma sessile, the lobes plane ; gynophore conspicuous ; ovary and fruit densely 

 pubescent on the inner surfaces of the locules. Secretory cells absent in the leaflet 

 mesophyll. Known only from northern Amazonia. Subg. 3. Sohnreyia. 



Spathelia Subg. 1. Spathelia. 



The fourteen species included in this subgenus are restricted to the Bahamas, 

 Cuba, and Jamaica; the eleven that are endemic to Cuba are distinguished in a 



