534 



PHANEROGAMS. 



A NGI OS PERM SI. 



Monocotyledons and Dicotyledons are distinguished from Gymnosperms by 

 the following characters : — their ovules are formed within a receptacle, the Ovary ; 

 the endosperm originates in the embryo-sac only after fertilisation, — characteristics, 

 the importance of which has already been shown in the general introduction to 

 Phanerogams. Concurrently with these distinctions there are however a number 

 of other peculiarities in these plants taken as a whole which distinguish them from 



Fig. -^^T.—Akebia quinata; A part of an inflorescence, v female, O male flowers ; B a male flower cut through length- 

 wise, c its sterile carpels ; C horizontal section of a female flower (magnified) ; D horizontal section of a male flower ; 

 E gynjeceum of the female flower with the sterile stamens a; /^ an ovary cut through horizontally ; G an ovule ; H horizontal 

 section of an anther ; « (in 5 and C) the outer, a' the inner stamens, c (in E) the carpels ; / (in ^ and C) the perianth. 



all other vascular plants ; and this is especially the case with the structure of the 

 flowers and the fruit, the normal morphological relations undergoing such peculiar 

 combinations and changes that a more detailed description of them must precede 

 the special description of the two classes which they include. 



The Flower as a whole ^. The flower of Angiosperms is rarely terminal, t. e. the 

 primary stem, which is a prolongation of the axis of the embryo, rarely terminates 



^ From ay^eTov, a receptacle, capsule, ovary, and avfpfxa, seed. 



^ The most important and comprehensive work on the flowers of Angiosperms is Payer's Traite 

 d'Organogenie de la Fleur (Paris 1857), with 154 plates. Also Van Tieghem, Rech. sur la structure 

 du pistil (Mem. des savants etrangers, XXI. 1871), and his notes in the French edition. [Eilcher, 

 Bliithendiagramme, and Gray, Structural Botany.] 



