1913] PACE—APOGAMY IN ATAMOSCO 385 
einem typischen Teilungeschritt erfahren, was eine Verdoppelung der Chromo- 
somenzahl zur Folge bat. 
This was the state of the problem when I left Bonn. 
A new collection was made this last autumn. Even from this 
collection the division of the mother cell has not been obtained. 
As was stated above, the development of the sac must go on very 
rapidly, for in some ovaries certain ovules are in the mother cell 
stage while others have mature sacs; and these seem not to be 
related to any part of the ovary or to follow in any special succes- 
sion; they occur apparently without any order. The buds appear 
at the surface of the soil one day with the mother cell undivided 
and the flowers are open the next and usually last only one day; 
so the whole development must go on very rapidly. 
There is no evidence that permanent walls came in at the 
division of the mother cell. The two-nucleate sac (fig. 5) never 
shows any evidence of disintegrating megaspores; so it belongs to 
the Lilium type described by CouLTER and CHAMBERLAIN (5, Pp. 
73), in which these two nuclei are the daughter nuclei without 
separating walls, and the nuclei of the four-nucleate sac are the 
four megaspore nuclei without separating walls. A discussion of 
this question was given in the paper on Cypripedium (19), and also 
by Courter (4). A recent paper by Brown and SHarp (2) shows 
this condition, and the same view is presented. 
The third division in the sac I was fortunate enough to get in 
eee si 
nearly all the ovules of one ovary. In many of these the chromo- | 
somes were quite distinct and several counts were made (figs. 6, 7, 
9). In all cases approximately 24 chromosomes could be counted. 
The sporophyte number is 24 (fig. 8); therefore the reduction 
division seems not to have taken place. This gives the egg the 
sporophyte or diploid number of chromosomes; and, according to 
STRASBURGER’S definition, when such an egg develops an embryo 
without fertilization it is a case of apogamy. He says (26, p. 80): 
Daher ich das Kriterium fiir echte Parthenogenesis in der Weiterentwick- 
lung eines Geschlectsproduktes erblickte, das mit der ihm normal Zukom- 
menden haploiden Chromosomenzahl anhebt. Wenn ein diploides Ei einen 
keim bildet, so bezeichnete ich dessen Entwicklung als Apogam, das Ei selbst 
als apogames Ei. 
inl 
