109 



( e ) Long after Wilhelm Hofmeister wrote " in (lessen [Pollen- 

 schluuch d. Coniferen] Innerem vielleicht Samenfaden sich bilden," (1) 

 spermatozoids have been found in Ginkgo biloba <2) and Cycas revoluta [%) 

 for the first time in 1896 ; and the behavior of their pollen in regard 

 to the process of fertilization has been found to be similar (4;) . 



(/) The " kurztrieb " of Ginkgo is exactly similar in all essential 

 morpological points to the stem of Cycadacece- ; they are both usually 

 unbranched, but sometimes copiously branched. 



Thus we see that Ginkgo and Cycas is so near to each other that 

 Ginkgo is more closely related to Cycas than to most other genera of 

 Coniferce ; but at the same time they deviate from each other in the 

 following respects : — (a) In Cycas pollen-sacs are borne on the under 

 surface of the staminal leaf, while in Ginkyo they are borne on the 

 margin of the sporophyll ; (b) Ginkgo has "Langtriebe'' and "Kurztriebe," 

 while Cycas has " Kurztriebe " only ; and their leaves are greatly 

 different in form, habit, and structure ; (c) the embryo of Ginkgo has 

 no suspensor, while that of Cycas has one. 



The formation of sporangia on the margin of leaves, the lobed 

 dichotomously-veined leaves, and the formation of spermatozoids are 

 the most remarkable points which Ginkgo and some ferns have in 

 common. 



Such a plant as Ginkgo might have been derived from some kind of 

 Ferns, but not from Lycopodiacece, to which many other genera of 

 Coniferce are closely related. In fact, Coniferce may be a heterogeneous 

 group ; and Ginkgo may be properly established as a distinct family 

 among G y vino sper race, that stands between Cycadacecz and Coniferce as 

 one of the four main branches of Gymnospermce, but not as a connect- 

 ing link between Cycadacece and Coniferce. 



{Concluded.) 



Botanical Institute, Science College, Imperial University, 

 Tokyo, Dec. 17th, 1896. 



(!) Vergl. Untersuchungen u. d. Saraenbildung d. Coniferen. p. 140 (1851). 



(2) , (4) . S. Hirase. On the Sperniatozoid of Ginkgo biloba (Japanese). The Eot. Mag. 

 Tokyo, Vol. X., No. 116, Part. % p. 325. 



(3) ) f4) . S. Ikeno. On the Sprematozoid of Cycas revoluta (Japanese). The Bot. Mag. 

 Tokyo, Vol. X., No. 117, Part I, p. 367. 



