488 



BOTANY 



I'AUT II 



!']<;. -4.J3. /."mi" Jlnriilmiit. An ovum 

 immediately after the fusion of the 

 nucleus of a ipflmtnoU with the 

 female nucleus has taken place. The 

 ciliary kind of the s]>ermato/<>i<l re- 

 mains in the upper portion of the pm- 

 toplasm of the ovum. Aseconil spev- 

 inaU'/.oid has attempted to enter the 

 OVUIP. (x 18, after H. J. WEBBER.) 



liy tin- elongation of a suspensor. It ulti- 

 mately' possesses a pair of large cotyledons, a 

 well -developed plumule between these and a 

 relatively short hypocotyl (Figs. 450-453). 



Order 2. Ginkgoinae ( t; ) 



The single representative of the Family of 

 the Ginkgoaceae which forms this order is 

 Hiiikijti tiiloba. This tree comes from Japan 

 hut is often seen in cultivation in Europe. 

 The long-stalked leaves resemhlc those of an 

 Adiantum, and are divided dichotomously into 

 two or more lobes. The llowers are dioecious. 

 The numerous stamens are situated on an 

 elongated axis which bears no enveloping 

 leaves. Microsporangia with an " endotheciuin" 

 (cf. p. 503). Macrosporangia in pairs at the 

 summit of short shoots ; sporophylls reduced to 

 a collar-like outgrowth around the base of the 

 sporangium (Figs. 454, 455). 



The development of the sexual generation 

 and the fertilisation is very similar to what has 

 been described for Znmio. The fertilised ovum 



Fi<:. 454.-';i;iJtyo biloba. Male branch with flower; the leaves an- iu.t yet full grown. 0, >>. 

 stamens ; c, female flower ; ./. fruit ; >. stone of same : /, stone in cross section ; <7, in lonjd- 

 tmlinsil section showin.u the emtiryo : h. female (lower with an exceptionally lar-e Dumber 

 of ovules borne on separate stalks. (Male (lower and <-. nat. si/e ; ./, slightly r.-<luce.) ; the 

 i.thi-r ti-ui-s nia^iiiiied. AfVr RICHARD : u-d after EICHLF.R.) 



