Doyle — Observations on the Morphology of Larix Icptolepis. 319 



in view of comparatively early cone development, it did not seem advisable 

 merely to follow the periods named for other forms. With the aid of the 

 data so acquired it was hoped to make collections in 1916 that would yield 

 an accurate and complete series of stages. But on the tree available there 

 appeared in 1916 only about half-a-dozen cones. In the spring of 1917— the 

 hard spring — the tree, on the advent of mild weather in mid-March, bore a 

 profusion of young female cones, and prospects seemed rosy ; but, on visiting 

 the tree on the morning following two nights of sudden and severe frost, 

 every cone was shrivelled and dead. It was decided then to commit to 

 paper such facts as had appeared in the 1915 gatherings, and to relinquish 

 the intention of completing the work. 



A. Tlie Female Strobilus, and Pollination. — When freed from the bud- 

 scales the lower part of the cone-pedicel is clearly covered with small leaves, 

 which gradually pass into the bracts subtending the still small axillary 



ate d e 



Fig. 4. — Outline drawings to show the gradual transition from small vegetative leaf at 

 base of cone to typical cone bract of Larix leptolepis. x 6. 



ovuliferous scales — a passage which is gradual in every sense. Text-fig. 4 

 shows the change in the structures themselves, from the typical small 

 needle-leaf on the left to the typical cone-bract of Larix on the right. The 

 complete similarity between the lowest leaf-structures and ordinary vegeta- 

 tive leaves is evident from PI. XVIII, fig. 5, a photograph of structure "a" 

 in the text-fig. 4, in transverse section. The double canal still persists in 

 the typical bract, well up in the cone (PI. XVIII, fig. 6). The axillary 

 structure also gradually changes. Appearing first in the axil of the bract at 

 stage " c " it is only a bump of sterile tissue, while slightly higher up an 

 ovule, which never matures, can be seen embedded in it. Then, at last, well 

 into the cone, it shows the form of the typical young scale, with two good 

 ovules. For the demonstration, if such were desired, of Professor Bower's 

 " Selago " condition in Gymnosperms, no better object could be found than 

 the megasporangiate strobilus Larix. When the cone is about one inch long 

 it is of interest that the ovuliferous scales are of little larger size than is 



3 f2 



