300 . The Botanical Gazette. (July, 
in the ovule, suggesting a sporangium which indeed it is, for 
the ovule certainly stands for a macrosporangium with its‘in- 
tegumentary covering or indusium. Although the presence 
of more than one embryo-sac in an ovule has been observed 
by several investigators in widely separated families, yet 
further research will undoubtedly show the phenomenon to be 
still more prevalent and widely distributed. Just now far 
this fact will throw light upon the origin of the angiosperms 
remains yet to be seen, but it certainly contributes materially 
to the phylogeny of the seed plants. 2 
The production of a series of four cells by two successive 
divisions of the initial cell of the embryo-sac, occurs more 
frequently in this family than had hitherto been supposed; and 
it seems probable that a more extended search in those genera 
in which this phenomenon was not observed by myself would 
reveal its occasional presence. 5 
In connection with the foregoing facts several questions 
naturally arise upon which it is not my purpose to speculate 
at present. What is the significance of the fact that in the 
same species the initial cell gives rise sometimes to only three 
cells and sometimes to four? Is the behavior of the initial 
cell due to inherent tendencies alone, or is it determined 
partly by external forces? Which is the more primitive con- 
of the same family a tapetum was absent; but no other in- 
stance is now known to me in which a tapetum was only of 
occasional occurrence in the same species. 
_ The rule so general in its application among angiosperms, 
that the lower cell of the series derived from the initial cell 
develops directly into the embryo-sac, seems to have a prob- 
able exception in Caltha (fig. 16). Guignard speaks also of 4 
probable exception in Acacia albida, and in the same place 
refers to a case reported by Mellink in one of the monocoty- 
ledons (Agraphis), together with the analogous case described 
by Strasburger for Rosa livida,}} 
10Embryogénie des Legumineuses. Ann. des Sc. Nat. Bot. VI. 12: —- 
11], c., PB. 537, 
4 
