126 BOTANICAL GAZETTE 



FEBRUARY 



to proceed from separate bract and scale to the fused bract and 

 scale is noted; in the first group the bract and scale are separate 

 almost to the base of the appendages, and both are about equally 

 prominent. To this group belong Keteleeria, Psendotsuga, species 

 of Abies, and species of Larix. 



Male gametophyte. — The multiplication of the cells in the 

 male gametophyte follows the sequence characteristic of the 

 Abietineae. There are 3 successive primary divisions; by the first 

 and second the 2 polar (" prothallial ") cells are cut off, the third 

 resulting in the formation of the antheridial cell and the tube 

 nucleus (figs. 1-5). This stage is the most advanced found in 

 available material, and is believed to be the stage at which the 

 pollen is shed. With respect to the development of the male 

 gametophyte at the time of shedding, Keteleeria would resemble 

 Pinus and might be contrasted with Abies and Picea. The 

 appendage-like outgrowths of the exine and the inflation of the 

 region between the exine and intine, caused by this growth, result 

 in the production of wings, such as are characteristic of the 

 Abietineae. 



The mitoses involved in the development of the male gameto- 

 phyte are similar to those described for Abies and Picea (12,13). 

 In each of the first 3 mitoses the spindle fibers become oriented in 

 such a way that they surround the polar nucleus; later they radiate 

 from it, appearing in cross-section as tufts of fibers. This pecul- 

 iarity of the mitotic figure doubtless is associated with the unequal 

 apportionment of the cytoplasm to the resulting nuclei, an in- 

 equality which results in more favorable conditions for the more 

 centrally placed nucleus. 



In Keteleeria the development of the male gametophyte is not 

 uniformly as described. Fig. 5 shows 4 nuclei medianly placed 

 and almost equal in size. The association of such gametophytes 

 with others whose nuclei and cells are unequal and differently 

 placed indicates that the degree of development depends upon 

 conditions, rather than being foreordained. When inclosed by a 

 wall containing little cytoplasm the nucleus soon disintegrates. 

 Fig. 4 shows 3 nuclei which are "prothallial" in nature; the third 

 under ordinary conditions would be regarded as antheridial; in 



