440 Lazvson . — The Gametophytes , Fertilization and 
cellular tissue. The prothallium thus passes through a stage when the 
majority of its cells are binucleate. After this binucleate cellular tissue has 
been organized, nuclear division proceeds in the usual way, and cell-plates 
are formed between the daughter-nuclei. 
The archegonial initials make their appearance just before the prothallial 
tissue is thoroughly organized. They are nearly always peripherical cells. 
There are four neck-cells, and a ventral canal-nucleus is cut off before 
fertilization. The archegonia are arranged as in the Cupresseae, that is, in 
a single group at the apex of the prothallium. They are surrounded by 
a common layer of jacket-cells, but these latter are sometimes found between 
the archegonia. The jacket-cells are multinucleate, and their characters 
suggest that they may be sterile archegonia. 
A single male cell enters the archegonium, and after the wall surround- 
ing it breaks down the sex-nuclei fuse. The first segmentation-spindle is 
organized in the centre of the archegonium just about the place where the 
fusion of the sex-nuclei occurred. After the second division the four free 
nuclei pass to the base of the archegonium and undergo another division, 
but meantime the nuclei have been arranged in two tiers. Walls are now 
formed between the nuclei, and then the nuclei of the upper tier divide. 
The walls formed between these latter are at right angles to the long axis 
of the archegonium, but the upper tier forms no membranes between its 
nuclei. The embryo now consists of two tiers of cells and one tier of free 
nuclei. The middle tier develops into long, tortuous suspensors, which 
carry down the embryo cells at their tips. There may be one or several 
embryos developed from a single archegonium. 
As near as could be estimated, there are nine or ten chromosomes 
in the nucleus of the gametophyte, and eighteen or twenty in the 
sporophyte. 
The gametophytes and embryo of Cryptomeria are distinctly of the 
Cupresseae type. 
Literature Cited. 
Arnoldi, W. (’00) : Beitrage zur Morphologie der Gymnospermen : III, Embryogenie von 
Cephalotoxus Fortuni. Flora, lxxxvii, p. 46, 1900. 
(’00) : Beitrage zur Morphologie einiger Gymnospermen : I. Die Entwicklung des 
Endosperms bei Sequoia sempervirens. Bull. Soc. Imp. Nat. Moscou, 1900. 
(’00) : Beitrage zur Morphologie und Entwicklungsgeschichte einiger Gymnospermen : 
II. Ueber die Corpuscula und Pollenschlauche bei Sequoia sempervirens. Bull. Soc. Imp. 
Nat. Moscou, 1900. 
(’01) *• Beitrage zur Morphologie einiger Gymnospermen : V. Weitere Untersuchnngen 
uber die Embryologie in der Familie der Sequoiaceen. Bull. Soc. Imp. Nat, Moscou, 1901. 
