THE CARROT AND PARSNIP FAMILY. 155 



IV.). A usual feature is the presence of five primary 

 ridges on each mericarp, shown as slight elevations in 

 Bit' ton (Fig. 63, IV.) and as points in the Hemlock 

 (V.), but are much stronger in the Fennel (Fig. 64). 



On some fruits there are four secondary ridges 

 between the primary. They are prominent in the 

 fruit of the carrot, in which they take the form of 

 a row of spines like a comb (Fig. 65). 



Some fruits have no ribs at all, being quite smooth 

 all over. 



The next point to notice is the presence 

 of oil-sacs called vittce. The usual number 

 is six in each mericarp, four on the outer 

 surface (Fig. 63, IV., v) and two on the inner 

 or commissural surface (wanting in Bu'hon). 



The seed fills up the ovary-cell, and ^of th*e 7enJei! 

 consists of a mass of endosperm (IV., V., a). ' 

 The embryo is embedded in it, but is not seen in the 

 sections (IV., V.), as, unless this be made high up, the 

 embryo is missed in cutting it across. 



Hydrocot'yle. — This genus has seventeen species. 

 Some have long, linear, i.e. narrow and grass-like, leaves ; 

 in others they are quite round or heart-shaped, or 

 again i}eltate, the petiole supporting the blade in the 

 middle like a round " shield." It differs from most 

 members of the order in having its flowers in sessile — 

 that is, stalkless, or " seated " — clusters, or as simple 

 umbels. The fruits have no vittce. 



