From the Bulletin of the Tohkrv Kotanical Cud, 35 : 303-308. n^oS 



The genus Ernodea Swartz : a study of species and races '=' 



Nathaniki. Lord Britton 



This genus of Rubiaceae was established by Swartz t on a 

 single species, E. littoralis Sw., from the island of Jamaica. It 

 has recently been regarded as monotypic, consisting only of the 

 type species, which is widely distributed in the Caribbean region, 

 in Jamaica, Florida, the Bahamas, and from Santo Domingo to 

 Guadeloupe. I do not find the genus reported from Cuba, though 

 it almost certainly exists there and further exploration will prob- 

 ably reveal it. Attempts have been made to refer to Er)wdca plants 

 now relegated to the genus Putoria of the Old World and to 

 Isidorca of the West Indies. 



In 1905 Dr. Small characterized Ernodea ajigusta % from pine- 

 lands in southern Florida, and in the same year I described 

 Er?iodea Cokeri § found among the collections made by Professor 

 Coker on Abaco Island during the Bahamian exploration organized 

 by the Geographical Society of Baltimore. The Bahamian explora- 

 tions conducted by the New York Botanical Garden and the Field 

 Museum of Natural History have revealed the existence in the 

 Bahamas of several additional species with apparently numerous 

 races, the genus evidently having its greatest development in these 

 islands. These explorations have afforded convenient opportunity 

 for field study of the plants. 



The shrubs form colonies sometimes of large size, spreading 

 from underground parts so as to clothe densely the sand or rocks 

 on which they grow. So far as our observation goes, they are 

 confined to limestone rocks or limestone sand. That mutation 

 takes place freely is indicated by the fact that in the Bahamas, at 

 least, one colony will often differ from another near by in some 



* This treatment of a genus will serve to illustrate the propositions advanced by 

 the writer in the symposium on " Aspects of the Species Question," at the meeting of 

 the Botanical Society of America, Chicago, January, 190S. 



fProdr. 29. 1788. 



+ Bull. N. V. Bot. (Jard. 3 : 438. 



\ In Shattuck, The Bahama Islands, 264, Botany by W. C. Coker. 



203 



