280 



ON SEEDLINGS 



FIG. 541. Ipomcea hispida. 

 Half nat. size. 



Cotyledons unequal, with petioles 3-5-4-5 cm. long, 2-8 cm. 

 wide, quadrangular, bilobed, cordate at the base, rounded at the 

 apex of each lobe, five-nerved at the 

 base or, more correctly, giving off 

 two strong primary nerves from each 

 side of the midrib, the latter termi- 

 nates in a small fork near the sinus, 

 and the nerves become incurved and 

 join near the apex of the lobes ; 

 strong secondary nerves are given off 

 from the basal pair of primary ones ; 

 reticulated, quite glabrous, thin, yel- 

 lowish-green above, paler beneath. 

 Stem herbaceous, twining, with 

 long internodes about 1 mm. thick, 

 terete, pubescent, with deflexed 

 hairs, pale green. 



Leaves alternately incurvi- 

 nerved or radiately at the base, 

 reticulate, more or less pubescent, 

 deep green above, paler beneath. 



Nos. 1-3. Long-petioled, simple, 

 3-5-5 cm. long, cordate or subcordate, acute, entire, palmatinerved 

 at the base, alternately nerved along the midrib, slightly pubescent, 

 thin, bright green above, paler beneath ; petiole slightly pubescent, 

 pinkish. 



Ipomcea Roxburg-hii, Steud. 



Ovary as in I. purpurea. 



Capsule dehiscing by the three valves separating from the septa, 

 almost invariably six-seeded ; valves thin, rather brittle, pale 

 brown. 



Seeds trigonous, testa rather cartilaginous when dry, pale or 

 dirty white, with the micropyle close to the round basal hiluin, which 

 faces obliquely the inner angle of the cell, somewhat marked by the 

 crumpled cotyledons within. 



Endosperm surrounding the large embryo, colourless- while the 

 seed is yet immature, afterwards cartilaginous when dry, thin and 

 membranous at places where the cotyledons press upon it, and 

 forming larger solid masses between the folds of the embryo. 



Embryo large, green at first and becoming dirty white when 

 mature and dry ; cotyledons deeply bifid, cordate at the base, five- 

 nerved, with the midrib becoming forked a little below the sinus, 



