Fig. 3 1 1 . — Pimts laricio: stages in the development of the male gametophyte; A , the 

 second reduction division; B, tetrahedral arrangement of microspores; C, the wings are 

 beginning to appear; D, prophase of first division in microspore; E and F, telophase of 

 first division; in !•', the nucleus of the first prothallial cell is already disorganizing; G, 

 first prothallial cell and prophase of second division; H, telophase of second division; /. 

 two prothallial cells; J , telophase of third division; the nucleus nearest the prothallial 

 cell will belong to the generative cell and the other is the tube nucleus; A', the two pro- 

 thallial cells, overlaid by the intine (/), the generative cell and the tube cell; this is the 

 shedding stage; Z,, pollen tube, as found in nucellus, showing stalk and body cells: />, pro- 

 thallial cells; J, stalk cell;/;, body cell;/, tube nucleus; e, exine; A and B, May 3; C, May 

 10; D-C, May 20; 11 -J , May 25; A', June 15; /., May i, nearly a year after the stage 

 shown in A ; X600. — From Coultf.r and Chambf.rlain, M orphology of Gymnos perms.^^ 



