250 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
COMPARISON OF CHARACTERS WITH THOSE OF COCOID PALMS. 
GERMINATION CHARACTERS. 
Some of the cocoid palms, such as Acrocomia, afford a suggestion 
of the method of germination followed by the palmettos and wax 
palms by a creeping rootstock. The seedling of Acrocomia does not 
have a long burrowing cotyledon, but the first four or five joints of 
the stem grow downward into the ground, forming a thickened, sub- 
terranean bulb that serves apparently for the storage of the food 
materials that are soon removed from the seed. After this subter- 
ranean structure has been developed the stem turns abruptly upward 
to begin the formation of the trunk. In Manicaria, which grows only 
in very wet swamps; neither of these specielizations § is found. The 
young plant appears much like a young Attalea, but there is no 
elongated cotyledon to carry it away from the seed. The same 
unspecialized method of germination is found in some of the species 
of Astrocaryum that are natives of very damp forests. 
The fact that Acrocomia and Attalea, both members of the family 
Cocaceae, have specialized in different ways in their methods of 
germination may be considered as evidence of derivation from the 
more simple state represented by Manicaria and Astrocaryum. The 
very close agreement of Phytelephas and Pseudophoenix with the 
more specialized Attalea method of germination is also suggestive of 
the idea that these aberrant genera may have arisen as offshoots of a 
primitive cocoid type. 
ENDOCARP CHARACTERS. 
But if such a history be projected to account for the agreement of 
Pseudophoenix with Attalea and Phytelephas in methods of germina- 
tion, the divergence from the primitive cocoid stock must be supposed 
to have taken place before the development of the composite endocarp 
that now appears as the most striking characteristic of the cocoid 
series. 
That the coalescence of the endocarps may have taken place inde- 
pendently in the ancestors of the different groups of Cocaceae is not 
to be considered as an impossibility in view of the several apparently 
independent cases of coalescence of the exocarps in other families 
of palms. The fact that many of the relatives of Acrocomia (sub- 
family Bactridineae) have the coalesced endocarps perforated by 
apical foramina, while other Cocaceae have only basal or peripheral 
foramina, would seem to support the idea that the coalescence of the 
endocarps might have occurred independently in the two groups. 
The coalescence of the endocarps would naturally have been preceded 
by a strong tendency to coalescence of the exocarps, as illustrated in 
Phytelephas, Manicaria, and Pseudophoenix. 
