CONIFERALES (TAXACEAE) 



341 



Ginkgo, but in Phyllocladus the nucleus (or nuclei) becomes free. 

 As a consequence, the spores on the tip of the nucellus are found 

 to contain three or four nuclei, one or two of which are vegetative, 

 and the body cell. In Dacrydium (136) the generative cell is cut 



Figs. 392-396. — Pollen grains of several podocarps: stalk, body, and prothaUial 

 cells evident; fig. 392, Phyllocladus alpina, showing an evanescent and a persistent 

 prothaUial cell, also stalk, body, and tube cells; X950; after Miss Yotjng (174); 

 fig. 393, pollen grain of Microcachr-ys ietragona at the shedding stage; after Thomson 

 (163); figs. 394, 395, Saxegothaea conspicua; fig. 394, the two prothaUial cells, the 

 generative cell, and the tube cell are in a line; X700; after Noren (149); fig. 39S) 

 later stage, showing body cell, and nuclei of tube, stalk, and three prothalUal ceUs; 

 also several large starch grains; X700; afterT>J'0R:6N (149); &g. 3^6, Podocarpus tolarra 

 Hallii; the usual condition of pollen grain at the shedding stage, containing tube 

 nucleus, stalk and body cells, and eight prothaUial cells (only four shown) derived 

 from the two primary prothalUal cells; after Biirlingame (139). 



off immediately after the two prothaUial cells, and then it and the 

 second prothaUial cell divide. In some cases {D. Bidwillii) usually 

 only the second prothaUial ceU divides, but in others (D. laxifoUum 

 and D. cupressinum) both prothaUial ceUs divide. The result is 

 that at pollination the spore contains three or four free vegetative 

 nuclei, in addition to the body ceU and the stalk and tube nuclei 



