1915] 



BRITTON VEGETATION OF MONA ISLAND 43 



HIPPOMANE MANCINELLA L. 



Common on the coastal plain: Porto Rico; Hispaniola; Bahamas; Curacao. 



CHAMAESYCE MONENSIS Millsp. 



Limestone plateau, Ubero: Endemic. 



CHAMAESYCE PORTORICENSIS (Urban) Millsp. 



On limestone rocks, Ubero and Sardinera: Porto Rico. 



CHAMAESYCE SERPENS (HBK.) Small 



Moist soil, coastal plain and plateau : Porto Rico. 



CHAMAESYCE HYPERICIFOLIA (L.) Millsp. 



Common in cultivated ground on the coastal plain: Porto Rico; Hispaniola; 

 Bahamas; Curacao. 



CHAMAESYCE BUXIFOLIA (Lam.) Small 



Common on coastal sands: Porto Rico; Hispaniola; Bahamas; Curacao. 



AKLEMA PETIOLARIS (Sims) Millsp. (Euphorbia petiolaris Sims.) 

 Common on the coastal plain and on the plateau: Porto Rico. 



POINSETTIA HETEROPHYLLA (L.) Kl. & Garcke 



Sandy beach, Playa de Fajaro: Porto Rico; Hispaniola; Bahamas. 



PEDILANTHUS LATIFOLIUS Millsp. & Britton, sp. nov. 



Shrubby, about 6 feet high, the young branches zig-zag, puberulent. Leaves 

 ovate to ovate-orbicular, 4.5 inches long or less, very nearly sessile, dull-green, 

 acute at the apex, roundish or subcordate at the base, very inconspicuously 

 veined, glabrous, the midrib elevated but not keeled beneath. Inflorescence termi- 

 nal, cymose, puberulent, bracteate; bracts lanceolate, acute, 3.5-4x2 lin., some- 

 what exceeding the peduncles; involucre about 10x4.5 lin., glabrous without and 

 within, tube narrow anteriorly, main lobes lanceolate-oblong, rounded obtuse, 

 ciliate at the apex, the accessory lobes equal or nearly so connivent with the 

 main lobes to near the ciliate apices, fifth lobe elongate-ligulate, truncate ciliate, 

 somewhat shorter than the accessory lobes and nearly closing the superior fissure 

 of the tube; appendix large, strongly saccate, about one-third the length of the 

 tube, split for half its length into two sarcous, ligulate slightly grooved and 

 emarginate lobes; glands 4, of two sorts: the upper pair reniform at the summit 

 of a broadly triangular stipe which is connivent with the surface of the appendix, 

 anterior margins free and sharp; lower pair about one-half the size of the upper, 

 discoid, peltate on a very short, free pedicel. Male pedicels numerous, glabrous ; 

 female pedicel glabrous; ovary glabrous; style 3-lobed at the apex, the stigmatic 

 branches bifid. Fruit unknown. 



Castle Point, Bermuda (Brown & Britton, 820, type). Near Bath, Jamaica 

 (Britton, 3^91). Baracoa, Cuba (Bemis). Sanchez, Santo Domingo (Rose, 

 Fitch & Russell, 4397). Mona Island (Britton, Cowell & Hess, 17S6). Perhaps 

 indigenous at the Santo Domingo locality cited; at all the others an evident 

 escape from cultivation, or in gardens. 



METOPIUM TOXIFERUM (L.) Krug & Urban 



Common on the coastal plain and on the plateau: Porto Rico; Hispaniola; 

 Bahamas. 



COMOCLADIA DODONAEA (L.) Urban 



Frequent on the plateau: Porto Rico; Hispaniola. 



RHACOMA CROSSOPETALUM L. 



Frequent on the coastal plain and on the plateau: Porto Rico; Hispaniola; 

 Bahamas ; Curacao. 



GYMINDA LATIFOLIA (Sw.) Urban 



Occasional on the coastal plain: Porto Rico; Hispaniola; Bahamas. 



