14 BOTANICAL GAZETTE [JANUARY 
IKENO,‘* and in Zamia by CouLTER and CHAMBERLAIN,’ but later 
stages have not been closely followed for any cycad, and the results _ 
now presented fill in some of the gaps still remaining in our 
knowledge of this interesting group. 
Description 
The intraseminal development of the embryo for descriptive 
purposes may be divided into four stages, each of which passes gradu- 
ally into the next: (1) the differentiation of a small mass of meriste- 
matic tissue at the base of the proembryo; (2) the rapid division and 
elongation of a group of cells at the proximal end of this meristematic 
tissue, forming the suspensor; (3) the differentiation of the cotyledons 
and stem apex; (4) the development of plumular leaves and the fusion 
of the distal halves of the cotyledons. 
The youngest stages figured are from the embryos of Encepha- 
lartos villosus (figs. 1, 2). Fig. z represents a stage in the develop- 
ment of the suspensor, the embryo being shaded. Fig. 2 is drawn 
from a slightly older embryo, showing the latter in detail and a small 
part of the suspensor. The small group of actively dividing cells, 
about 40-50 in number (12-16 in sections), which is forming the 
suspensor, can be recognized readily by the fact that the cells are 
arranged in regular longitudinal rows. 
The remaining figures (3-78) are from embryo of E. Friderici- 
Guilielmi.° Fig. 3 represents the only case met with in which the 
suspensor was branched, the branches bearing two equally developed 
embryos. The figure shows the two branches of the suspensor only 
up to the point of junction; the suspensor was injured in sectioning 
just above this point, and it is impossible to say whether the branching 
is dichotomous or monopodial. 
Fig. 4 is an outline of a longitudinal section of an embryo at the 
close of the second stage of its development. The part inclosed by a 
4 IkENO, S., Untersuchungen iiber die Entwickelung der Geschlechtsorgane und 
der Nae! der Befruchtung bei Cycas revoluta. Jahrb. Wiss. Bot. 32:557-602- 
pls. 8-10 
5 mace ‘5 M., AND CHAMBERLAIN, C, J., The embryogeny of Zamia. Bor. 
GAZETTE 35:184-194. pls. 6-8. 1903. 
© This appears in Index Kewensis as a synonym of E. cycadifolius, but Dr. PEAR- 
SON informs me that he finds the two species to be quite distinct. 
