22 



ON SEEDLINGS 



fully occupied by a straight embryo. Again, in the Ash 

 (Fraxinus) (fig. 46), Ursinia (fig. 47), &c., the cotyledons lie 

 parallel to the longer axis of the seed, which is narrow and 

 elongated. Such cases, however, are comparatively few ; and 

 there are a large number of species in which the seeds are 



FIG. 47. Achene of Ursinia spe- 

 ciosa. Longitudinal section, 

 x 2. Transverse section, x 10. 



PIG. 48. Chenopodium Bonus-Henri- 

 cus, vertical and transverse sections 

 of seed. 



broad and even orbicular, while yet the cotyledons are narrow, 

 as for instance in Chenopodium (fig. 48) and Menispermum 

 (fig. 49). 



FIG. 49. Menispermum canadense. 



A, germinating, seedling, 

 C, transver 



x 2. B, vertical section of seed, x 4. 



verse section of seed, x 2. 



In these it will generally be found that the cotyledons lie 

 transversely to the seed. In Menispermum (fig. 18) the 

 fruit (fig. 49) is laterally compressed and horseshoe-shaped, 

 with a crest along the edge ; the seed (fig. 49, B) conforms to 

 the shape of the fruit, and the embryo is curved and linear, 

 the cotyledons being applied to oue another face to face, and 

 at right angles to the plane of the seed, so that the edges of 

 the cotyledons touch the walls of the seed at each side. 



