250 GINKGO. 



afforded sufficient reason for the institution of a separate- 

 subdivision of the Gymnosperms in which to include Ksempfer's- 

 genus. 



Ginkgo is sometimes spoten of as unknown in a wild condition, 

 but this statement has recently been challenged by Mrs. Bishop- 

 (Miss Bird), who speaks of having "met with several fine- 

 specimens in the magnificent forests which surround the sources of 

 the Gold Eiver and the smaller Min in Western China." ' 



The genus Ginkgo, as represented by the single li-ving species 

 Ginkgo liloha, may be diagnosed as follows : — 



A tree of pyi-amidal form reaching a height of over 30 metres, 

 ■with smooth grey bark, characterized among existing Gymnosperms 

 by its flat, broad leaves, with the Cyclopteris type of venation, 

 deciduous in the autumn, possessing a long and slender petiole- 

 slightly grooved on its upper surface and a lamina varying con- 

 siderably in size and shape, occasionally fan-shaped and entire, but 

 more frec[uently di-vided into two halves by a more or less deep- 

 median division, or subdi-vided into several wedge-shaped lobes. 

 The foliage-leaves occur either scattered on long shoots or crowded 

 at the apex of short shoots ; the latter form of leaf -bearing axis 

 often passes by apical gTowth into the long shoots bearing scattered 

 leaves separated by long internodes. 



Flowers dioecious. The male flowers, which occur in the axils 

 of scale-leaves, have the form of a stalked central axis bearing 

 scattered, loosely disposed stamens ; each stamen consists of a 

 slender filament terminating in a very small apical scale, bearing 

 usually two, sometimes three or four, elliptical pollen-sacs which, 

 open by longitudinal dehiscence. The pollen - grains develop a 

 rudimentary prothallus consisting of a few cells, and before 

 fertilization two large spirally coiled multiciliate spermatozoids are- 

 produced from the generative nuclei in the pollen-tube. The 

 female flowers usually have the form of a long peduncle bearing 

 two terminal elliptical ovules enclosed at the base by a coUax-like 

 envelope representing a reduced carpellary leaf. Abnormal female 

 flowers, possessing more than two ovules, are not infrequently met 

 with. Each ovule consists of a nucellus enclosed by a single 



' Letter to the London Standard, Aug. 17, 1899. Vide also Bird (80), vol. ii.. 

 p. 144. 



