CONIFERALES (TAXACEAE) 



339 



Taxodineae and Cupressineae among Pinaceae; and the unequal 

 male cells, possibly related to the fact that the archegonia are not 

 organized into a complex, a feature found among Abietineae. The 

 exceptional condition in Cephalotaxus is that the inequality of the 

 male cells is not so marked, and may disappear entirely through lack 

 of wall-formation. 



The male gametophyte 

 of the Podocarpineae has 

 attracted so much attention 

 that every genus (except 

 Pherosphaera) has now 

 been investigated, and the 

 peculiar condition of the 

 vegetative (prothallial) 

 tissue is found to belong 

 to all of them (figs. 389- 

 396). It appears that this 

 feature of the podocarps 

 was first described and 

 figured in 1896 by Thibout 

 (43) for Podocarpus poly- 

 stachya. 



The first peculiarity of 

 the tribe is that the pollen 

 grains are winged, except 

 in Saxegothaea (149, 150), 

 a character that has suggested a connection with Abietineae, the 

 only other tribe of conifers with winged pollen grains. The 

 situation in Microcachrys (151, 163), however, taken in connection 

 with the wingless spores of Saxegothaea, suggests that wings may 

 have arisen quite independently in this tribe. In Microcachrys the 

 wings are not so definite in development or in number as in Podo- 

 carpus and Dacrydium, in which two well-developed wings occur. 

 Thomson (163), examining sixty-four pollen grains, found fifty 

 with three wings, nine with four, two with five, and three with 

 six. In every case the wings are comparatively small, variable 

 in size, and late in development. Three wings are also found in 



Fig. 388. — Cephalotaxus drupacea: the two 

 sperm nuclei within the body cell; the stalk 

 nucleus (smaller) and tube nucleus are in advance; 

 May 23, 1904. — After Lawson (130). 



