The cocoid palms are a distinctly American group, the African oil-palm, _Elaeis Guineensis_ and the cocoanut being the only outliers of the family which have been supposed to be indigenous in the Old World. South America is the center of distribution and is the home of a large proportion of the two hundred or more species. Only five genera reach Puerto Rico, and one of these, _Cocos_, was probably not a native of the island. Key to the Subfamilies of Cocaceae Trunks, stems, and midribs beset with sharp spines; seeds foraminate at or above the middle. Subfamily BACTRIDINAE. Trunks and other parts unarmed; seeds foraminate at base. Subfamily COCINAE. Subfamily BACTRIDINAE Some of the numerous South American representatives of this group are nearly smooth, but the three genera known from Puerto Rico have the trunks, leaf-bases, midribs and inflorescences beset with sharp black spines, and are thus readily recognizable. Key to the Genera of Bactridinae Trunk small, cespitose; leaves separated by long internodes; foramina of seeds apical. BACTRIS. Trunk medium or large, solitary; leaves crowded together at the summit; foramina peripheral. Trunk slender; leaf-divisions broad, praemorse-truncate; pistillate and staminate flowers intermixed on the inflorescence; exocarp fleshy. CURIMA. Trunk robust; leaf-divisions narrow, sharp-pointed; pistillate flowers below and separate from the staminate; exocarp fibrous. ACROCOMIA. BACTRIS Jacquin, Stirp. Am. 279. _pl. 271._ 1763 The type of this genus, _Bactris minor_ Jacquin, described from the vicinity of Carthagena, Colombia, is a small spiny palm with creeping rootstocks. The upright trunks are about an inch thick and twelve feet high, with long spiny internodes. The fruits are fleshy, purple, and about the size of a cherry. Several species of _Bactris_ are known from the West Indies though the generic name has doubtless been applied rather loosely to all the small spiny cocoid palms. The two following species of _Bactris_ from Puerto Rico described by Martius several decades ago seem not to have been secured by recent collectors unless it be true, as suggested below, that one of them, the simple-leaved _B. acanthophylla_ applies to a young _Curima_. Of _B. Pavoniana_ the narrowly grass-like leaf-divisions would be sufficiently characteristic to separate it at once from all other palms known from Puerto Rico. BACTRIS ACANTHOPHYLLA Martius, Palm. Orbign. 67