SIZE AND FORMS OF COTYLEDONS 



61 



Some of the Onagrarieas have seedlings with very curious 

 cotyledons. For instance, I was greatly puzzled by the seed- 

 ling of (Enothera bistorta, in which (fig. 105) the cotyledons 

 were long and linear, suddenly widening at the end into a 

 large orbicular expansion, which gives them a very peculiar 

 appearance. 



In Eucharidium grandiflorum (fig. 108) the form of the 

 cotyledon might not unnaturally be supposed to be a case 

 similar to that of Malva. In reality, however, the explanation 

 is very different. In Eucharidium the lobes have nothing to 



PIG. 106. Seedling of Eucharidium 

 grandiflorum, x 3. 



FIG. 107. Eucharidium grandiflorum : 

 ten days after germination, x 3. 



do with the arrangement of the embryo in the seed. The 

 young plant, indeed, immediately after germination, presents 

 no trace of them. The cotyledons, when they first emerge 

 from the seed (fig. 106), are oblong-orbicular, sessile, cordate 

 or auricled at the base, and emarginate at the apex, with a 

 small purple tooth in the notch : they grow rather rapidly, 

 become shortly petioled, and develop one or two lateral, 

 incurved nerves on each side of the midrib. 



In the next stage, about eight days after germination, they 

 exhibit a very slight constriction near the base of the coty- 

 ledons, with a small obtuse tooth. This basal portion increases 



