88 



ON SEEDLINGS 



involucel, oblong, apex conical, base obtuse, crowned with the 

 ultimately deciduous calyx and marked longitudinally with eight 

 ridges ; pericarp extremely thin and membranous except on the 

 ridges. 



Seed oblong, conical at the tip, conforming to the outline of the 

 ovary, which it completely fills ; testa extremely thin and mem- 

 branous ; hilum at the extreme upper end of the seed and incon- 

 spicuous. 



Endosperm copious, fleshy, white, surrounding the embryo. 



Embryo straight, large, nearly equal in length to the seed; 

 cotyledons oblong, obtuse, entire, plano-convex, embedded in the 

 endosperm which is thinnest at the edges of the cotyledons and the 

 radicle ; radicle very stout, slightly and suddenly narrowed at the 

 tip which is close to the apex of the seed, about one-third as long 

 as the cotyledons. 



Seedling (fig. 447). 



Primary root stout, long, tapering, 

 with numerous lateral fibres, biennial. 



Hypocotyl subterranean, stout, 

 colourless, about 1 cm. long. 



Cotyledons subfoliaceous, gla- 

 brous, petiolate ; lamina oval-oblong, 

 entire or minutely emarginate, 12 mm. 

 long, 7 mm. wide ; petiole flattened, 

 7 mm. long. 



Stem herbaceous, erect, and 

 elongating the second year when 

 about to flower. 



Leaves simple, radical and ulti- 

 mately cauline, opposite, exstipulate, 

 radical ones petiolate, cauline ses- 

 sile, and connate by their bases, hairy 

 on both sides, pale green, nerved and 

 reticulate with ascending and sub- 

 incurved nerves, entire or toothed ; 

 petioles rather broad, channelled, 

 slightly winged upwards. 

 First pair spathulate, obtuse, subentire or shallowly and obso- 

 letely crenate. 



Second pair similar, shallowly crenate with long petioles. 

 Third pair oblong- spathulate, obtuse, shallowly crenate, decur- 

 rent on the long petioles. 



FIG. 447. Dipsacus sylvestris. 

 Half nat. size. 



