22 ON SEEDLINGS 



of its cotyledons turned towards the axis, in order to find 

 accommodation during the process of germination in the 

 laterally flattened fruits. The embryo in the transverse 

 section of the mericarp appears to be eccentric, but this 

 phenomenon is due to the mericarp being suddenly narrowed 

 on the dorsal edge near the apex. The fruit of Chaerophylluin 

 aureum is narrowly oblong, and dorsally compressed, with the 

 commissural face much the broadest. Contrary to what we 

 should expect, the cotyledons have their edges instead of their 

 backs to the axis, notwithstanding the fact that they He in 

 the narrowest plane of the seed. Owing to the seed being 

 deeply grooved along the ventral face, the species belongs 

 naturally to the fourth group of which it is an anomalous 

 member. In like manner Carum Carvi (fig. 410) should be- 

 long to the first group, seeing that its mericarps are almost 

 regularly pentagonal. The embryo is nearly half the length 

 of the endosperm, but it is very erratic in its behaviour 

 inasmuch as the cotyledons sometimes have their backs to 

 the axis (which is probably the most typical case), sometimes 

 their edges, or again are placed obliquely, that is, diagonally 

 to it. The various inclinations seem to be assumed indiffer- 

 ently, and the embryos even frequently occupy different posi- 

 tions in the two halves or mericarps of each fruit. 



Seedlings. While still in the seed the width of the coty* 

 ledons is limited by that of the seed itself. 



After germination, however, they may become more or less 

 modified by further growth ; but the form they attain in the 

 seed becomes deeply impressed upon them, and the chief 

 alteration is in length, especially in that of the petioles. 



Those observed may be arranged in five groups more for 

 convenience' sake than from absolute distinction between the 

 several types, for there is every intermediate gradation. In 

 the first may be classified all those in which the lamina of 

 the cotyledons is short and relatively broad. It varies from 

 ovate, spathulate, and oblong to oval, and is generally if not 

 always distinctly petiolate with the petioles free, or connate 

 at the very base only. The cotyledons of Hydrocotyle vulgaris 

 (fig. 405) are ovate, subsessile, and very small. They exactly 

 correspond with the size and shape of the mericarps. The 



