1909] MCALLISTER—-EMBRYO SAC OF SMILACINA 207 
cases, and the mere loss of the division membranes cannot affect 
their morphological value. 
Some preliminary studies of Smilacina racemosa seem to show 
that the two outer nuclei, formed in the double division of the embryo 
sac mother cell, undergo two further divisions to form the eight nuclei 
of the mature embryo sac. I shall describe this species, with other 
related species, more fully in a later paper. 
Recent studies have brought to light an increasing number of 
so-called atypical methods of embryo sac formation, which must be 
considered in attempting its phylogenetic interpretation. 
In Eichhornia, according to SmirH (22), a cell plate is rarely 
formed between the two nuclei resulting from the first division of the 
embryo sac mother cell, and a cell plate is also rarely formed between 
the daughter nuclei of the second division. Reduction takes place 
and one of the four megaspores forms the embryo sac. 
CAMPBELL (2, 3) reported the discovery of the 16-nucleate embryo 
sac of Peperomia pellucida, and in the following year JOHNSON (13); 
working independently, published an account of the same species. The 
embryo sac mother cell develops directly into the embryo sac. The 
sixteen nuclei organize to form an embryo sac with an egg apparatus 
Consisting of an egg and one synergid. Six nuclei are cut off singly 
around the periphery of the embryo sac, and the remaining eight 
nuclei fuse to form the endosperm nucleus. Later JOHNSON (14) 
reported that in Peperomia hispidula fourteen out of the sixteen 
nuclei of the embryo sac unite to form the endosperm nucleus. 
In contrast with the large number of nuclei in the embryo sac 
of Peperomia, is the embryo sac of Helosis guayanensts, which es 
reported by CHopat and BERNARD (7) to contain only four nuclei 
when mature. This 4-nucleate embryo sac is due to the disintegra- 
hon of the lower nucleus of the first embryo sac division, so the prod- 
ucts of the division of the upper nucleus alone enter into the embryo 
Sac structure. 
Avena fatua has been shown by CANNON (5) to form its mega- 
Spores Similarly to Eichhornia. Commonly no cell walls are formed 
Detween the four spore nuclei, but the lower of these nuclei develops 
into the embryo sac and the other three degenerate. 
A case resembling that of Avena and Eichhornia is reported as 
