GROUP V. ANGIOSPERMJE ; DICOTYLEDONES. 



541> 



cular bundles, five generally on each mericarp ; of these, two run 

 along the margins (Fig. 361 B, C, D, rr\ and the other three along 

 the dorsal surface (Fig. 361 B, <7, Z), r). In the spaces between 

 the ridges which form furrows, lie oil-ducts or receptacles (vittce) 

 (Fig. 361 B, C, o), and sometimes other secondary ridges (juga. 

 sccundaria) (Fig. 361 E, F, n), which do not enclose vascular 

 bundles. The mericarp when ripe is filled by the seed, which 

 consists of the abundant endosperm (Fig. 361 C, D, F, e~) enclosing 

 a small embryo. According to the form assumed by the endosperm, 

 the following groups may be distinguished : the OrthospcrmecK r in 

 which the surface of the endosperm, which is directed towards the 

 plane of junction of the two mericarps, is flat or convex, as in 

 Carum (Fig. 361 C) : the Campylospermece, 

 in which the endosperm is concave to- 

 wards the same plane, as in Conium (Fig. 

 361 D], and the Coelospermece, in which 

 the whole endosperm is curved, so that it 

 is seen to be concave towards this plane 

 both in longitudinal and in transverse 

 section, as in Coriander (Fig. 361 F). 



The flowers, with few exceptions (Hy- 

 drocotyle, Astrantia, Eryngium, where the 

 umbels are simple), are in compound um- 

 bels (p. 440) ; in some few cases, as in 

 Caucus, the umbel has a distinct terminal 

 flower which is black in colour: an in- 

 volucre and involucels are largely de- 

 veloped in some species, in others they are 

 wholly wanting. The hollow stem bears 

 large leaves with generally well-developed 

 sheathing bases and much divided laminae : 

 rarely the leaves are simple, as in Hydro- 

 cotyle and Bupleurum. 



The British genera are arranged as follows : 

 Sub-order I. ORTHOSPERMK.E. 



A. Umbels simple. 



Tribe 1. Hydrocotylece. Fruit laterally compressed. The genus Hy< In. - 

 cotyle consists of marsh-plants with peltate leaves (Fig. 22). 



Tribe 2. Saniculece. Fruit nearly cylindrical. This group includes 

 the genera Astrantia, Eryngium, and Sanicula. 



B. Umbels compound. 



Tribe 3. Amminece. Fruit without secondary ridges, laterally com- 



Fia. 362. Fmit of Caram. 

 Carui. A Ovary of the flower 

 (/). B Ripe Fruit. The two 

 carpels have separated go a* 

 to form two mericarps (m). 

 Part of the septum consti- 

 tutes the carpophore (a). 



