15 



their position or from any other circumstance can be regarded as 

 carpels." (1) "He states, also, in the classification of ovules with respect 

 to their position, that the lateral ovules may be regarded as the 

 equivalent of whole leaves. (2) 



Braun has also observed no carpels in Taxaecce. Gcebel seems to 

 be of opinion that the ovule of Ginkgo is an axial structure, the 

 direct terminal formation of floral axis itself, (3) and not of its branch 

 as considered by Strasburger. 



Masters regards the cup-shaped swelling at the base of the ovule 

 as an imperfectly developed aril/ 4; 



I may state here in passing that Asa Grey's explanation of his 

 figure of Ginkgo seed in his "Structural Botany" is not true. For he 

 states: U A drupaceous seed of the same [G. biloba] in vertical section, 

 exhibiting the mature disk which forms flesh. " (5J By this explanation 

 we are led to suppose that the cup-shaped swelling at the base of the 

 ovule becomes afterwards the pulpy portion of the seed. 



As to the seed of Ginkgo, Strasburger states that since no 

 fibrovascular bundles are developed, in the integument they cannot be 

 regarded as the cause of the formation of the prominent edges of the 

 stony part, though they may be regarded so in the case of Taxtis ; and 

 since in the prominent edges there have never been detected even special 

 cell rows, he considers the edges as a formation derived by inheritance 

 from the seed which had no fibrovascular bundles in the integument. (6) 



(To be continued.) 



diText Book of Botany, p. 516 (1882). 



C2)1.c. p. 575. 



(*> Outlines of Classification and Special Morphology, p. 385 (1887). 



(4) Journal of the Linnean Society, Botany, Vol. 27, p. 300 (1891). 



t^loc. cit. p. 271 (1880). 



W Die Coniferen und die Gnetaceen, p. 15 (1872). 



