70 MARGARET C. FERGUSON 



CHAPTER III. 

 Macrosporogenesis. 

 the female cone. 



The Macrosforangiuni. — During this investigation I have 

 made no attempt to study the early development of the ovule 

 except to note definitely the date of its origin. The pistillate 

 strobili cannot be detected in Pimis Strobiis with the most careful 

 examination until the last of April or the first of May. In the 

 other species studied they are about one and one-half milli- 

 meters long at the middle of March, and it is possible that in 

 these species they were organized in the autumn, but I have not 

 been able to find any evidence that such is the case. I have 

 recently, November 25, 1902, attempted to discover the young 

 cones of Pinus rigida and P. atcstri'aca, but, as formerly, the 

 search was futile. I was led to look again for these strobili in 

 the autumn by the recent statement of Coulter and Chamberlain 

 ('01). On page 79 of their book on the morphology of the 

 Gymnosperms, I find this sentence, based on a study of Pinus 

 Lai'icio : ** In June the archegonia are ready for fertilization, 

 which occurs about the first of July, at least twenty-one months 

 after the first organization of the ovule." This by a very simple 

 mathematical calculation places the " organization of the ovules " 

 on October i. 



I have not only been unable to detect the pistillate cones 

 before the approach of winter, but in tlie tin}^ cones of Piniis 

 rigida^ P. aitslriaca and P. montana uncinata, fixed on March 

 14 there is not the least suggestion of ovules, the entire 

 cone consisting in each case of a broad axis on the margin of 

 which are slight elevations or papillaj — the beginnings of the 

 bracts which subtend the ovuliferous scales (fig. 121, plate 

 XII). The first indications of the ovules are found in these 

 species about the last of April or the first of May. In material 

 of Pinus Strobus fixed on May 31, 1898, the position of the 

 ovule can be detected only by a slight bulge on the inner sur- 

 face of the ovuliferous scale, the integument not 3'et having 

 been differentiated. One week later, June 6, the ovule is 



