52 ON SEEDLINGS 



EABLY DEVELOPMENT OF FRUIT AND SEED. 



Fruits frequently occur that are obtusely trigonous, indicating 

 the ancestral form of the tricarpellary ovary, while in the young 

 condition the cavity of the ovary is perhaps always slightly 

 trigonous. 



When the fruit has grown to some size, but long before maturity, 

 the young growing seed is rotund-obovate or almost orbicular and 

 very much shorter than the cell which it occupies. 



The raphe at this stage passes round one side, along the apex, 

 and a short way up the other side of the seed. 



Further growth proceeds below the chalaza ; the raphe also 

 keeps pace with this localised growth and consequently attains 

 its great length, nearly surrounding the margins of the flattened 

 seed. 



When the seed has attained full size, it is orbicular, or nearly 

 so, biconvex or lenticular, and much compressed dorso-ventrally, 

 rather acutely two-edged, and completely fills the cavity of the 

 ovary; the raphe encompasses all but a short part of the edge, 

 corresponding to the part above it in the ovule or exceeding it 

 but a very little. 



Seedling (fig, 422). 



Hypocotyl erect, terete, glabrous, reddish, stout at the base and 

 tapering upwards, 1-1'5 cm. above the soil. 



Cotyledons oblong, obtuse or submucronate, entire, sessile, deep 

 shining green, glabrous, tapering to the base and connate, tri- 

 nerved at the base, with the nerves incurved about or below the 

 middle, and uniting with other two that run nearly parallel with 

 the midrib and margin, becoming incurved and uniting with the 

 midrib close to the apex, slightly reticulate, 9-12 mm. long, 3-4 mm. 

 wide. 



Stem erect, two-angled in the earliest seedling form with the 

 angles running down from the edges of the pair of leaves next above 

 them, ultimately four- or many- angled or ridged and furrowed, 

 glabrous, pale green, ultimately shrubby ; 1st rnternode 6-15 mm. 

 long. 



Leaves simple, cauline, opposite, first few pairs exstipulate, 

 ciliate, pubescent beneath, at least when young (first pair ciliate 

 only), strongly palmately trinerved and lobate, coarsely, acutely and 

 irregularly dentate, with the principal nerves again strongly alter- 

 nately nerved and reticulate, deep green above, paler and shining 



