208 BOTANICAL GAZETTE [SEPTEMBER 
of this cell is haploid or diploid. WuNKLER also maintains that 
other factors besides the number of chromosomes determine the 
character of the gametophyte as well as the sporophyte. Yama- 
NOUCHI’S (42) studies on apogamy in Nephrodium support this 
hypothesis. If we accept STRASBURGER’S narrow definition of the 
egg, it seems logical to restrict the term gametophyte to structures 
having the haploid number of chromosomes, that is, to bodies 
developed after a normal sporogenesis. Regarding Dendroph- 
thora opuntioides from this point of view, a true megaspore formation 
does not occur, the gametophytic generation itself is omitted, and 
the nuclei of the embryo sac are thus really vegetative or sporo- 
phytic in character. If the egglike cell in Dendrophthora, as well 
as in other similar cases, is a vegetative or sporophytic cell, it is 
strikingly different in behavior from all other sporophytic cells 
which we know. 
I find no record among seed plants of the origin of an embryo 
from a cell of an endosperm-like mass, which like that of Dendroph- 
thora has been derived from a single egglike cell. If this cell is 
really a vegetative cell of the sporophyte, we should expect it to 
develop directly into a sporophyte, as nucellar cells do in Coele- 
bogyne and Funkia. In Antennaria alpina (Juet 16) or Thalictrum 
Fendleri (Day 4), for example, the egg cell which develops without 
fertilization should, if it is really a sporophytic cell, give rise to a 
sporophyte having the same sex as its parent. Furthermore, the 
derivation of the endosperm from a single polar nucleus is a peculiar 
phenomenon if this nucleus be regarded as sporophytic in character. 
In the ferns, aposporous prothalli whose nuclei contain the 
sporophytic number of chromosomes are distinctly different in 
structure and in possessing sex organs from the parent sporophytes. 
Hence chromosome number cannot be the sole morphogenic factor 
in the nucleus. If the nucleus in any way determines structure, 
it is evident that the nuclei of an aposporous embryo sac must 
differ in some manner from those of the parent sporophyte, in spite 
of the identity in chromosome number. Morphologically the 
nuclei of such an embryo sac may be said to be equivalent in the 
Same sense that the nuclei of a typical embryo sac are. The nucleus 
from which the embryo sac of Dendrophthora opuntioides develops, 



