492 



DICOTYLEDONES. 



are most frequently obcordate, or have an incurved apex (Fig. 528 

 B, (7), being incurved in the bud ; they are white, rarely yellow 

 (Fennel and Parsnips), blue or red. The flowers are sometimes 

 zygomorphic, especially those on the circumference of the umbel, 

 and in that case it is the petal which is directed outside 

 (anterior) which is the largest, and the two posterior are the 

 smallest {e.g. Heracleum). The stamens are incurved in the bud. 

 The 2 free styles unite at the base into the " stylar-foot " (stylopod), 

 a swollen nectary (Fig. 528 -B, 0) ; the ovary is bilocular, the raphe 



FIG. 528. Caucus carota with flower and fruit. 



of the ovules being directed inwards. The fruit is a schizocarp, 

 dividing into two mericarps; the plane in which these separate 

 coincides with that of the union of the carpels, and the two 

 nut-like mericarps are in most genera kept together for awhile at 

 the top of a thin, bifid, or undivided stalk (carpophore) which is in 

 direct continuation with the flower-stalk (Fig. 537). Each mericarp 

 has most frequently 5 more or less strongly projecting ridges, the 

 primary ridges (Figs. 530, 532, 534, 535, etc.), of which 3 lie on 

 the back of the mericarp, the dorsal ridges, and 2 on its edge near 

 the plane of division, the marginal ridges; five of these (10 ridges 



