554 OX SEEDLINGS 



remarkable in having one very large cotyledon, and one 

 minute scale-like one. 



A good type of the Order is represented by Clarkia sp. (fig. 

 356) which has amygdaloid cotyledons slightly emarginate and 

 cordate at the base. The emargination is due to a slight 

 thickening at the chalaza, and the basal auricles are produced 

 to occupy the space on each side of the base of the radicle. 

 The seeds of (Enothera Lindleyana are similar, but show 

 greatly elongated papillae at the chalaza. In <E. biennis (fig. 

 364) the embryo is generally amygdaloid and entire. Instances 

 occur where the cotyledons are slightly convolute with the edge 

 of the one folded within that of the other. The testa shows a 

 remarkable thickening hi places, while elsewhere it is com- 

 paratively thin. The embryo of Eucharidium grandiflorum 

 is like those of Clarkia sp. and (Enothera Lindleyana, except 

 that the base of the cotyledons is more deeply auricled. 

 There is a strongly developed crest at the apex of the seed, 

 passing round the chalaza, and extending nearly to the hilum, 

 and it is fringed at its margin with papillae throughout. 



Seedlings. The cotyledons of the various seedlings of this 

 Order show great variation, both in size and outline, and in 

 being entire or variously crenate, dentate, serrate or con- 

 stricted at the margin, even within the limits of a single 

 genus, so that it is often impossible to classify species of allied 

 genera under any one group. Two very distinct kinds, how- 

 ever, may be noted, namely those which are small or generally 

 so and entire, and secondly, those which attain a compara- 

 tively large size by intercalary growth whether entire or 

 variously cut. To the first group belongs Epilobium angusti- 

 folium which has small ovate, entire, obtuse, shortly petiolate 

 cotyledons, showing no other venation than the midrib. Here 

 also may be grouped a number of species of (Enothera ; but 

 for the sake of comparison with other species it is convenient 

 to describe them under that genus. 



Cotyledons that exhibit intercalary growth, and especially if 

 they attain any size, partake of two natures, and that often in 

 a marked manner. The upper part is the true cotyledon, 

 while the lower part, which is generally much the larger, is of 

 the nature of a true leaf, and varies in shape according to that 



