1909] THOMSON— POLLEN OF MICROCACHRYS 29 



pollen of P. dacrydioides as having normally three wings (op. cit., pi. 

 14, figs, io, 11). I have found three wings present exceptionally 

 in the usually two-winged P. jerruginea (fig. 12). Unfortunately, no 

 data nor material of the more probable genus Dacrydium were 

 available. 



The bi-winged condition of the pollen on the pines and podocarps 

 has often been referred to as an indication of affinity between the 

 groups. This view has no longer support, since the winging of the 

 grain has arisen in the Podocarpeae within the group itself, and so 

 is distinct from that of the pines. In a further contribution on the 

 character of the megasporophyll of Saxegothaea and Microcachrys, 

 the writer hopes to show the essential difference of this structure in 

 the two great phyla of the conifers. 



University of Toronto 



EXPLANATION OF PLATES I AND II 



PLATE I 



Twigs 



PLATE II 



Fig. 



1. 



icrosporangiate 



Fig. 2. — One of the same enlarged; the sporangia can be seen in pa 



eath the terminal scale of the sporophyll. X9. 



FlG - 3 — A microsporophyll in longitudinal section, to one side of the axis 



Fig. 4. 



sporangium 



fungus shown in contact with pollen grains in fig 



Fig. 5a. — The wall of the microsporangium in tangential 



Fig. 56. — The same in transverse section. 



Fig. 6.— A field of sectioned pollen grains; below is one with four wings; 

 above it one with three wings cut transversely and a small part of the body 

 uniting these; various other aspects of the wings. 



* IG - 7- — The microgametophyte. 



Figs. 8-1 i. — Pollen grains at same magnification: fig. 8, Microcachrys, 

 from below; fig m p, Saxegothaea; fig. 10, Podocarpus jerruginea (a and b two latera 

 views at right angles; c, dorsal view); fig. 11, Pinus resinosa. 



*ig. 12. — A three- winged grain of Podocarpus Jerruginea. 



