56 



EMBRYOGENY OF Pinus Pinaster. 



Ferguson (7) and others for various species. It is. however, interest- 

 ing to note the effect on the hfe history of the cHmate experienced 

 in Cape Colony, as compared to that in which Pinus has been 

 previously investigated. It should perhaps be mentioned that the 

 essential features of the climate of the south-western portion of 

 Cape Colon}^ are : (i.) a wet butnot very cold winter, and (ii.) a 

 dry and fairly hot summer, the latter starting about September 

 and ending about April, while the former occupies the remainder 

 of the year. Naturally, in the extra-tropical regions of the southern 

 hemisphere, the seasons differ by exactly six months from the 

 corresponding seasons in the north, and therefore to compare the 

 life history here with that in the north requires an alteration of 

 six months in the actual date at which a given stage is found here.. 

 For convenience this alteration has been made in the third column 

 of the table given below. The dates in Europe and America (which 

 are practically identical) are taken from the papers cited above. 

 The following table shows, therefore, the seasonal differences 

 between Pinus pinaster in South-Western Cape Colony and various 

 other species of Pinus in Europe and America, for some important 

 stages in the life history. 



TABLE OF DATES. 



Megaspore 

 mother-cell. 



May 27 to June 

 12. 



July and August. I January and Feb- 

 ruary. 



Megaspore 



First division of 

 Megaspore. 



June. 



August. 



February. 



End of July. 



Not seen. 



Prothallus with 

 32 nuclei (rest- 

 ing condition). 



October to end Dec. to May at June to November 

 of April. least (and pro- ! at least 



bably later), i 



Cell formation in 

 prothallus. 



About June i. 



About Oct. I. 



Young uninucle- 

 ate Arche- 

 gonium. 



About June 



9-15- 



October 6-27. 



Mature Arche- 

 gonium and 

 fertilisation. 



June 15 to July 



End of October 

 to November 

 9- 



About April i. 

 April (:>-2;-. 



End of April to 

 May 9. 



