156 BOTANICAL GAZETTE [AUGUST 
Gametophytes and embryo of Cunninghamia.—This monotypic Chino- 
Japanese genus has been investigated by Miyake, who has just published a pre- 
liminary notice’? of his results. The male gametophyte has no prothallial cells, 
and at pollination it consists of two nuclei (generative and tube). These two 
nuclei enter the pollen tube, in which the generative nucleus soon divides, one of 
the daughter nulcei entering into the structure of the rapidly enlarging body cell, 
and the stalk nucleus remaining free in the cytoplasm of the tube. Pollination 
occurs early in April, and the tube reaches the archegonial complex about the 
end of June. There is a solitary megaspore mother cell, which divides about the 
time of pollination. The embryo sac is invested by a distinct tapetal zone, and 
before the end of June is full of tissue. The archegonium initials appear early 
and the development of archegonia is rapid, the complex being fully formed by 
the end of June. This complex is singular in that the group of archegonia (15 
in the case illustrated) surrounds a central mass of sterile tissue. The cutting-0 
of a ventral nucleus and its rapid disorganization were observed, this division being 
promptly followed by fertilization during the first week of July. The fusion 
nucleus soon divides, and the two daughter nuclei pass to the base of the eg: 
Walls appear after eight nuclei are formed, which is apparently true for Pinaceae 
without exception. The proembryo comprises three tiers of cell, with the usual 
functions.—J. M. C. 
continuous to the very base; possess a well-marked centripetal xylem; 
the vascular bundles there is a complicated double sheath of transfusion a 
0 
coniferous leaves, which has been described by WoRSDELL as representing 
etal xylem, JEFFREY regards as a relic of the inner transfusion sheath. 
way he has connected Pinus with the Cordaitales through Prepinus; ae 
shown that the Mesozoic pines display transition characters between he 
and the pines of today. His conclusion is that the Abietineae are the oldest tt 
of Coniferales, and that Pinus is its oldest living representative —J- M. C. 
19 Miyake, Kitcut, The development of gametophytes and embryogeny ics 
ninghamia (Preliminary note). Bot. Mag. Tokyo 22:45-50. figs. 14- 1908. 
20 JEFFREY, EDWARD C., On the structure of the leaf in Cretaceous pines. 
of Botany 22:207-220. pls. 13, 14. 1908. 
