480 Stiles. — The Podocarpeae. 
the beginning of pollen-tube development up to fertilization has only been 
observed in two cases : in Podocarpus coriaceus 1 and Phyllocladus sp. 2 
A most excellent general account of the early stages of development 
has already been published by Coulter and Chamberlain, 3 and as the 
additional species examined by the writer behave similarly in this respect 
to those already observed, only a brief account of this part of the subject 
is necessary. 
As regards gross structure, the pollen-grains of Saxegothaea 4 are wing- 
less ; those of Microcachrys possess wings which are, however, small and 
variable in size and number, three being the most frequent number met 
with. In Phyllocladus , Dacrydium , and Podocarpus the wings are on the whole 
larger and are two in number, although three wings are found exceptionally 
in Podocarpus ferrugineap and normally in Podocarpus dacrydioidesp 
The feature of the gametophyte which has attracted most attention is 
the comparatively large development of prothallial tissue, a feature first 
noticed by Thibout 7 in Podocarp7is poly stachyus. In all the species so far 
investigated two prothallial cells are cut off successively, as in the Abietineae. 
In Saxegothaea 8 the second prothallial cell always divides into two daughter- 
cells, and the first often divides as well. This prothallial complex of three or 
four cells persists up to the time of pollination, which is as far as the develop- 
ment of the male gametophyte has been observed. An exactly similar con- 
dition probably obtains in MicrocachrysP An essentially similar condition has 
been found in Dacrydium Bidwillii , where, as a rule, only the second prothallial 
cell divides, and in D. cupressinum and D. laxifolium , where generally both 
prothallial cells divide. 10 A less active condition prevails in Phyllocladus p x 
where usually neither cell divides, although the second occasionally does so. 
In Podocarpus there is apparently a more variable condition. In P . 
coriaceus, Coker 12 found that the primary prothallial cells might divide 
amitotically. Jeffrey and Chrysler 13 found in P .poly stachyus , P .ferrugineus, 
and P. dacrydioides that both the prothallial cells might undergo two 
successive divisions, making a total of eight prothallial cells. Burlingame 14 
recorded a similar condition in P. Totara , var. Hallii , but reported a great 
deal of variation in the number of prothallial cells produced, namely, from 
one to eight, six being the most usual number. Mr. Brooks and the writer 
have found that as many as eight prothallial cells may be produced in 
P. spinulosusP As many as eight prothallial cells are also produced in 
P. andinus. 
1 Coker (’02), p. 94. 2 Young (’10), p. 82. 3 Coulter and Chamberlain (’10), p. 339. 
4 Norton (’08), p. 105 ; Stiles (’08), p. 213. 6 Thomson (’09 1 ), p. 29. 
6 Thibout (’96), PI. XIV, Figs. 10 and 11. 7 1. c., Figs. 8 and 9. 
8 Nor&i (’08), p. 106. 9 Thomson (’09 1 ), p. 28. 
10 Young (’07), p. 192. 11 Young (TO), p. S2. 
12 Coker (’02), p. 92. 13 Jeffrey and Chrysler (’07). 
14 Burlingame (’08), p. 169. 15 Brooks and Stiles (TO), p. 309. 
