106 ON SEEDLINGS 



other. In many cases, however, a large number of the species 

 belonging to the different types constitute groups which are 

 more or less closely allied and belong to the same genus or 

 tribe. 



As a fairly representative seedling with linear cotyledons, 

 I may refer to that of Ursinia speciosa with linear, entire, 

 fleshy, glabrous and sessile cotyledons. The first two leaves 

 are opposite and pinnatisect with linear segments ; succeeding 

 ones are more or less divided; and the ultimate ones are 

 again like the first. They are auricled at the base from the 

 fifth leaf onward and superficially appear to be stipulate. The 

 cotyledons of U. anthemoides are broader and longer, while 

 the first two leaves are like those of U. speciosa. The allied 

 Coreopsis gigantea (fig. 464) has much longer cotyledons than 

 either of the last two, and they are slender and somewhat 

 undulated. The primary pair of leaves are similar to those 

 of Ursinia speciosa, but the linear segments are longer. The 

 ultimate leaves are bipinnatisect with long, linear, slender 

 segments. The cotyledons of Bidens humilis (fig. 465) are 

 linear and very small. The leaves are opposite, dimorphic 

 and present a very interesting case of evolution. The first 

 pair are pinnatisect with linear segments, and succeeding ones 

 are two or three times pinnately cut or multisect. In a batch 

 of plants about half grown, many of them will produce leaves 

 on the upper part of the stem of a different character 

 from those described. They are ternately pinnatisect, with 

 triangular or ovate segments, generally cuneate at the 

 base, the terminal one largest and simply or doubly incise- 

 serrate. 



A number of species belonging to different genera may be 

 grouped together here on account of the resemblance of the 

 seedlings both as regards the cotyledons and the primary 

 leaves. They are mostly annual and the cotyledons are 

 narrowly linear, frequently semiterete, and the first pair of 

 leaves are opposite and'similar to the cotyledons, but longer 

 and rather broader especially above the middle. Coreopsis 

 filifolia and C. Douglasii are instances, at least as regards 

 the first pair of leaves. Eelhania sessiliflora has the first 

 seven pairs of leaves linear, entire, and gradually longer 



