iqisJ AASE—M EGASPOROPHYLLS OF CONIFERS 309 



In the second group based on vascular anatomy the bract and 

 scale vascular supplies are more or less intimately united into one 

 bundle which springs from the base of the cylinder gap. 



Of sporophylls with parts separate there belong here the lower 

 sporophylls of Pinus Banksiana, P. maritima, and Keteleeria 

 Fortunci (the ovules in these sporophylls are to greater or less 

 extent abortive), and Ccdrus Libani (2). Of the sporophylls with 

 parts considerably united there fall into this group those of Cun- 

 ningkamia, Arthrotaxis laxifolia (1), most species of Araucaria 

 (i> 3) 6, 7, 9, 10), and the lower sporophylls of Cryptomcria japoiiica, 

 Cupressus Benthamii, and Thuja occidentalis. Most of the appar- 

 ently simple sporophylls are included in this group, as those of 

 Agatkis, Saxegolhaea (5, 8), and Arthrotaxis selaginoides (1). 



The degree of welding of the bract and scale vascular supplies 

 varies considerably. In Arthrotaxis selaginoides, Agathis, Arau- 

 caria, and Saxegolhaea the two remain united into one bundle for 

 greater or less distance in the cortex; in most of the others the single 

 bundle divides early; but in many cases, where the two sporophyll 

 parts have fused extensively, branches of the scale supply swing 

 about to lie on the ventral side of the appendage at each side of the 

 bract bundle. This fact is well illustrated in Thuja occidentalis, 

 Juniperus communis, Cupressus Bcnthamii, and Cryptomcria 

 japoiiica. In Cupressus Benthamii and Cryptomcria japonica the 

 scale bundles at either side of the bract bundle even accompany 

 the bract bundle into the free portion of the bract. 



Bundle distribution is generally directly related to the size of the 

 organ supplied, hence the bundles extend into the most expanded 

 region of the sporophyll, whether that particular region represents 

 bract or scale. 



In Cunninghamia, Araucaria, and Agathis, in which absence 

 of sporophylls with separate bract and scale supplies makes com- 

 parison impossible, it is difficult to determine with certainty what 

 is bract and what is scale supply. The matter is further compli- 

 cated by the presence in the last two genera of a branching bundle 

 in the vegetative leaf, a condition which probably implies a branch- 

 ing bract bundle in the bract of the sporophyll as well. And, 

 further, Cupressus Benthamii and Cryptomcria have clearly shown 



