The dried fruits of Acrista are grayish brown in color and nearly smooth or somewhat coriaceous in external texture; they measure 11 or 12 mm. in length and are nearly as wide, being slightly oboval in shape. The outer wall is thin and brittle and covers a more or less distinct thin layer of amorphous brownish material probably representing the pulp of the fresh fruit; in the dry state this may adhere either to the outer wall or to the fibers next inside. Near the base these fibers are simple, pointed and vertical; about half way up they divide and anastomose and are, as it were, felted and cemented together to form an oval sac open below and closed above. The outer fibers are much coarser than the inner and there are sometimes suggestions of three layers separated by a dark-brown friable material. A few of the delicate inner fibers are adnate to the surface of the seed which is otherwise free from its fibrous covering.
Seed 8.5 mm. by 8 mm., slightly lighter in color than the outside of the fruit. Surface slightly uneven with obscure veinlike ridges and impressions of the fibers of the outer covering. The kernel is white, hard and bony, and deeply ruminate, though this is not apparent from the outside. The channels are very narrow and often radial and straight; they penetrate 3 mm. or less. Embryo directly basal; hilum lateral, somewhat below the level of the stigma; a short raphe extends about half way to the embryo.
Family COCACEAE
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.