624 



PART III.— THE CLASSIFICATION OF PLANTS. 



Order 1. Umbellifer^. Flowers generally regular, bat zjgo- 

 morphic in consequence of oligomerj in the gynaeceum (p. 508): 

 formula, K5, 05, ^5, G{i) • the calyx is generally very small, often 

 hardly visible, though sometimes well developed {e.g. Eryn- 

 gium, Astrantia) : the corolla consists of five rather small white or 

 yellow petals ; occasionally the outermost petals of the ttowers at 

 the circumference of the umbel are larger than the others, and the 

 umbel is then termed radiant : stamens five ; ovary inferior, bi- 

 locular : the base of the two styles is fleshy and thickened, forming 

 an epigynous disc (Fig. 426 A d) ; one suspended ovule in each 

 loculus of the ovary (Fig. 338 E) : the fruit, when ripe, splits 

 into two mericarps, each loculus of the ovary being permanently 



in n- rr ^ in 1, rr 



Fig. 426.—^ Flower of Foeniculum (mag.): / ovary; c corolla; s stamens ; d disc. B 

 Fruit of Heracleum : p pedicel ; g style ; r r r ridges (costae) : rr marginal ridges ; o oil- 

 ducts (vittse) (mag.)' C Transverse section of mericarp of Carum Carui {Orlhospenneoe) : 

 m surface that comes into contact with the other mericarp; o vittae : e endosperm. D 

 Transverse section of mericarp of Conium {CamjtylospermecB). E Fruit of Coriandrum, 

 {Ccelospermece) : fc margins of the surface along which the two mericarps are in contact ; r 

 ridges ; n secondary ridges : F section of a mericarp. (Mag.) 



closed by a median septum (Fig. 427a; see p. 530). The struc- 

 ture of the pericarp is an important characteristic for the classifica- 

 tion of the family. The fruit is commonly either oval in form, or 

 compressed (Fig. 426 B), or nearly spherical (Fig. 426 E) : its sur- 

 face generally bears longitudinal ridges {costm or juga primaria) en- 

 closing vascular bundles, five generally on each mericarp; of these, 

 two run along the margins (Fig. 426 B, C, D, rr), and the other three 

 along the dorsal surface (Fig. 426 B, (7, 2>, r). In the spaces be- 

 tween the ridges which form furrows, lie oil-ducts or receptacles 



