CUPULIFEILE 529 



towards one another at an early stage, and ultimately fleshy, 

 occupying the whole of the seed, wrinkled both internally and 

 externally, undulate and interlocking with one another at the 

 margin. 



Fagus sylvatica (the Beech) constitutes a fifth type. The 

 cupule consists of numerous bracteoles amalgamated in four 

 large pieces which completely enclose the two to four, generally 

 two fruits, and ultimately spread open to allow of the dispersion 

 of the latter, which are triquetrous with three wings extending 

 from the apex to below the middle. The seed is bluntly 

 trigonous and does not completely fill the angles of the 

 fruit. The fruit is three-celled in the ovarian stage, with two 

 anatropous ovules suspended from near the apex of each cell. 

 In nearly every case one ovule develops at the expense of the 

 rest. The ovary soon becomes one-celled by the rupturing of 

 the septa ; but the axial column remains attached to the apex 

 of the cavity and carries the anatropous seed suspended from 

 near the apex. The embryo at an early stage becomes doubled 

 upon itself longitudinally and covers two of the sides of the 

 triangular cavity. Then growth continuing at the edges of the 

 cotyledons the primary folds are pushed into the centre of the 

 cavity. The edges of the cotyledons become reversed towards 

 the angle of the ovary occupied by their middle portion ; and 

 when they have grown in this direction till they again meet 

 with resistance, they double back again so that in the full- 

 grown seed they consist of four folds so arranged as to fill 

 the trigonous seed and that again the triquetrous fruit. They 

 can therefore become aerial and green during germination, and 

 differ in these respects from any of those mentioned above. 



The greater number of the fruits of this Order are adapted 

 to be transported by animals, to which they serve as food. 

 Those of the Hornbeam, however, are winged. 



Seedlings. Four more or less distinct types coming under 

 my observation have aerial cotyledons, while in a fifth case 

 they are subterranean during germination. The simplest type 

 is that of Betula alba (fig. 672) which has small, oblong-ovate, 

 shortly stalked cotyledons, showing a faint midrib. The first 

 two leaves are ovate, followed by three more or less triangular 

 ones. The sixth is cordate. AU are unequally serrate and 



