﻿9-i Lloyd: On an abnormal cone 



near the ends of the vegetative shoots. In the pistillate shoots, 

 however, the axillary buds, throughout the greater part of its 

 length, are developed into the ovuliferous scales. The production 

 of these scales, therefore, upon a shoot normally vegetative would 

 seem to be due to excess of nutrition, in response to some sort of 

 irritation. Why the axillary buds thus forced into growth should 

 not become simply vegetative, instead of spore-bearing, may be 

 due to inherited tendencies, and if so, we have here a case of 

 atavism, a return to a condition during times long gone by, when 

 the sporophyte was chiefly or altogether sporogenous. Unfortu- 

 nately for this view, there is no little difficulty to be encountered 

 in harmonizing the facts derived from the study of teratological 

 • conditions found in the angiosperms, as, for example, the change 

 from carpel to foliage leaf. All that we can assert at present is 

 the interchangeable character of plant structures. 



Explanation of f*late 327. 



ft 



Figs, i-ii inclusive. A series of bracts from the pistillate shoot. 

 Fig. I. Leaf from pistillate shoot immediately below the cone. 

 Fig. 2. Bract from base of cone. 

 Fig. 11. Bract from tip of cone. 



Fig. 12. Lateral view of the apex of a bract from the abnormal cone. 

 Fig. 13. Normal leaf, X 3/2. 



fiG. 14. Leaf from the leader which produced the abnormal cone. 

 Fig. 15. Leaf taken from the leader immediately below the abnormal cone. 

 Fig. 16. Leaf subtending a scale in the abnormal cone showing the maximum 

 degree of lateral expansion attained. 



Fig. 17. A small portion of the leader bearing a leaf and, in its axil, a reduced 

 scale, X IS/ 1 ! s > scale; /, leaf; r, leaf-cushion. 



Fig. 18. Longitudinal section of same, X 20/1 about. Drawn with camera 

 lucida. 



Fig. 19. Tip of normal leaf, X 6/ 1. 



Fig. 20. Tip of leaf from leader in question, X6/i. 



Fig. 21. An abnormal, asymmetrically developed scale showing discrepancy of 

 growth between the two sides, X 3/2. 



