-512 BOTANICAL GAZETTE [june 



that "it is a natural thing to see in these three layers character- 

 istics of the testa in cycads, Ginkgo, and the older gymnosperms ; 

 and to conclude that the two integuments have arisen from a 

 single one by delaying the development of the region that becomes 

 the outer fleshy layer. These facts and the inference seem to hold 

 good also in the case of Taxus, the only difference being that the 

 outer fleshy layer (aril in this case) remains distinct from the 

 inner one." In Taxus this freedom of the aril and hard integument 

 exjtends to the base (fig. 43), probably due to the fact that the 

 development of the aril begins relatively late. Coulter and 

 Land's figure of the ovule of Torreya at the mother cell stage shows 

 considerable growth of the fleshy layer, while a corresponding 

 stage (fig. 40) in Taxus shows but the beginning of the aril primor- 

 dium. In Torreya there is a much greater and earlier chalazal 

 growth of the ovule, resulting in a larger seed than in Taxus, the 

 bulk of which is produced below the point of juncture of the fleshy 

 layer and the hard coat. 



In Taxus the inner fleshy layer may be represented only by the 

 inner epidermis, and possibly a few layers of cells in the basal 

 portion of the ovule, and is practically absent. The remainder 

 of the seed coat becomes hardened, with the exception of the 

 epidermis and hypoderm. It hardly seems reasonable to regard 

 these two layers of cells as representing the outer fleshy layer, but 

 rather that their failure to develop the stony character is due to 

 their superficial position. ''The probability is that the stony 

 layer would not develop superficially in any event, so that it would 

 not be necessary to regard a layer or two of cells overlying it (the 

 hard coat) as representing the outer fleshy layer (Coulter and 

 Chamberlain- 9, p. 418). The inference is that the outer fleshy 

 layer is lacking in the Pinaceae, and from the same reasoning the 

 outer layer of the seed coat in Taxus need not be regarded as an 

 outer fleshy layer. Even the claim for two integuments in the old 

 Cordaitean seeds is based on weak evidence, and the seed coat 

 there "may correspond to the outer fleshy layer and stony layers 

 of the single integument of cycads and Ginkgo" (Coulter and 

 Chamberlain 9, p. 174). Scott (32) also calls attention to the 

 possibility of this view. It is likely that only a single integument 



