OXAGRAEIE^E 561 



First pair of leaves ovate, obtuse, alternately incurvinerved, 

 distantly and shallowly serrate-dentate, often minutely tricuspidate 

 or tridentate at the apex. 



Second pair narrower, oblong-ovate, otherwise similar to the first. 



DEVELOPMENT OF THE COTYLEDONS. 



The cotyledons immediately after germination are oblong- 

 orbicular, minutely emarginate, with a small tooth in the notch, 

 slightly auricled at the base, sessile, with a scarcely discernible 

 midrib. 



They then enlarge, become orbicular or broadly obovate, sub- 

 cuneate at the base, and shortly petiolate. Fig. 357, A, shows a 

 specimen three days after germination. 



A change now occurs at the base of the cotyledons, which is at 

 first narrower and soon becomes conspicuous by the presence of a 

 small tooth on each side, as is shown in Fig. 857, B, which repre- 

 sents a seedling five days after germination. 



The new portion elongates, bearing two to four teeth on each 

 side, and the whole cotyledon becomes oblong, with a broad emar- 

 ginate upper half consisting of the true cotyledon, and a basal nar- 

 rower half which is truly foliolar with the characteristic white and 

 reddish midrib of the true leaves, and the marginal teeth ; petiole 

 now 1-5-2 mm. long. (Ten days after germination.) (Fig. 357, C.) 

 The cotyledons now become broadly ovate, cuneate at the 

 base, petiolate, and all or most of them more or less distinctly 

 alternate ; the lower part or innovation has four to six small 

 obtuse teeth on each side, and is broadly subelliptic in outline, 

 minutely ciliate at the margin. The upper part or true cotyledon 

 is comparatively small, suborbicular, emarginate, with a tooth in 

 the notch. (Eighteen days after germination.) 



Clarkia rhomboidea, Douglas (figs. 359, 360). 



Seeds 1 -25-1 '5 mm. long, and as wide near the apex. 



DEVELOPMENT OF COTYLEDONS. 



The cotyledons are at first orbicular, entire or faintly emar- 

 ginate with a prominent apical tooth, sessile, and like the hypocotyl 

 purplish, glabrous, but soon become minutely papillosely pubescent. 



Nine days after germination (fig. 359) they are obovate or sub- 

 panduriforrn, emarginate with a small tooth in the notch, constricted 

 below the middle, denoting the line between the upper part or true 

 cotyledon which is minutely pubescent, and the lower part or 

 innovation which is much more conspicuously pubescent with a 



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