COXVOLVULACE^E 273 



way to the base. The first two leaves are roundly ovate ; the 

 second spathulate ; and the third obovate, and emarginate. 

 A fifth very distinct group centres around Ipomcea Quanioclit 

 (fig. 540) which has deeply bipartite cotyledons with linear, 

 widely divaricate segments traversed by two nerves each. 

 The real length of the lamina is from the apex of the petiole 

 to the middle of the sinus, and is really very short. The 

 lobes represent lateral growth after the cotyledons can no 

 longer grow in length ; they are very much folded transversely 

 while still in the seed. The first two or more leaves are 

 deeply pinnatisect with linear lobes appearing as if pinnate. 

 I. dasysperma closely corresponds to this type, but the leaves 

 are different from those of I. Quamoclit. The cotyledons of 

 I. palmata are scarcely so deeply divided, and are rather 

 irregularly four- to five-nerved at the base, with strongly 

 ascending segments. The first three leaves are cordate, five- 

 to seven-nerved at the base, and trifid at the apex, or they 

 show a few more lateral teeth. The cotyledons of an 

 unnamed, subshrubby, and apparently climbing species of 

 Convolvulus are deeply bipartite with linear one-nerved seg- 

 ments. The first two leaves are lanceolate, while succeeding 

 ones up to the ninth differ chiefly in their much greater 

 length. An extreme limit of division is met with in Convol- 

 vulus Cneorum, an upright shrubby species with hoary and 

 silky foliage. The cotyledons are cut or divided, not only 

 to the base of the lamina, but into the petiole, giving rise to 

 four diverging, one-nerved segments resembling as many coty- 

 ledons. The first four leaves are oblanceolate, and narrowed 

 into a short petiole. 



The simplest type of cotyledons in the Order as far as 

 I have observed is that of the Nolaneae, whose peculiar cha- 

 racteristics have already been mentioned under seeds. Those 

 of Nolana atriplicifolia (fig. 543) are lanceolate-oblong, fleshy, 

 and indistinctly one-nerved. The first leaf is ovate and the 

 four succeeding ones are more elliptic. The cotyledons of a 

 Nolana from Santiago are narrowly spathulate, petiolate, 

 one-nerved, and pubescent. The first seven or eight leaves 

 exactly resemble the cotyledons in size, length, and hairi- 

 ness. 



