350 BOTANICAL GAZETTE [may 



tribution about the prothallium. It would be interesting to know the 

 condition in the mature seed, especially in view of the fact that in 

 certain species of Dacrydium the megaspore coat is very thick at a 

 later sta«;e. 



The integuments of the ovule are seen in their usual form mfig. ij. 

 Sometimes the inner one is quite open above the ovule (fig. 15), even 

 at an advanced stage. In the case figured it is developed laterals 

 into two large masses, appearing as additional ovules in gross material. 

 In other cases it may be uniformly quite thick (fig. 16). The two 

 outer cell layers of the integument are tangentially elongated in the 

 older condition, while the third consists of columnar cells radially 

 placed, many of which in the basal region become lignified and 

 have numerous large pits. They are in connection with the supply 

 bundles of the ovule through transfusion-like extensions of the latter. 



Fig. 1 j is of a longitudinal section of the bract and scale from the 

 megasporangiate cone of Tsuga canadensis. The section passes to one 

 side of the axis in the region of the ovule. To the lower right-hand 

 side of the figure the bract is seen fused proximally with the tissue-: at 

 the base of the scale. .The latter shows one large vascular bundle, 

 cut nearly transversely. This has the wood below and the bast above, 

 an arrangement the inverse of that in the bract. From this bundle i 

 given off the ovular supply, which passes obliquely upward into the 

 base of the sporangium. The character of the supply bundle was 

 studied in series of transverse sections. It comes off from one of the 

 lateral bundles of the scale (fig. 15; second bundle from the right 

 and left of the figure). Its wood and bast lie at first in a plane at 

 right angles to that of the scale bundles (fig. 19; the wood is the sma - 

 celled tissue in the center of the figure and the bast is to the let ). 

 Shortly the bundle turns completely round, so that its wood lies abme 

 and its bast below, the inverse arrangement to that of the scale bund es, 

 which, in turn, is inverse to that of the bract. Near the ovule t e 

 bundle becomes concentric and finally bifurcates, the branches en er- 

 ing the base of the integument. 



In the microsporophyll of the cycads Thibout 8 has called T a " e " 

 tion to the inverse orientation of tjie sporangial supply- 



I have 



8 Thibout, E., Recherches sur I'appareil male des gymnospermes. 

 16. Lille. 1896. 



pp. 265- P ls 



