266 Key to the System of 



Calyx-lobes white, as large as the petals. 



Alpine herb, much beset with spreading hairlets ; leaves 

 basal, from rhomboidal- to cordate-orbicular, short-lobed 

 and somewhat crenate ; flowers irregularly umbellate and 

 somewhat paniculate ; calyx-lobes almost alike to the 

 petals and along with them deciduous ; fruitlets narrowly 

 coherent, dorsally hardly convex ; terminal disk broadish. 



A. dichopetala. 



OREOHXirRRHXS. 



1218. Erect. 



Hardly or slightly branched ; leaves comparatively large, 

 much beset with hairlets, their segments numerous and 

 repeatedly divided ; umbel-stalks often much elongated ; 

 stalklets not rarely beset with ah appressed vestiture ; 

 petals minute, white, tinged with red ; fruit rather 

 turgid, contracted upwards. O. aiidicola. 



Prostrate. 



Cushion-shaped ; leaves comparatively small, glabrous, 

 with simple or bi- or tri-fid segments ; umbels few- 

 flowered, on very short stalks ; anthers dark-red; fruits 

 always much shorter than the stalklets. 



O. pulvinifica. 



HYDKOCOTYLE. 



1219. Leaves centrifixed. 



Perennial, creeping, semiaquatic or floating, of deleterious 

 properties ; leaves fixed at the centre to their stalk, 

 orbicular, lobeless, somewhat crenulated ; umbels capitu- 

 lar and solitary or additionally one to three whorls 

 of flowers below ; petals minute, pink ; fruitlets quite 

 compressed. H. vulgaris. 



Leaves quite or nearly basifixed 1220 



1220. Perennial ... 1221 



Annual ... ... ... ... ... ... 1226 



1221. Leaves almost or quite entire. 



Stem creeping and rooting ; leaves from cordate- to renate- 

 orbicular, entire or waved-sinuous, occasionally somewhat 

 denticulated ; umbels capitular, few-flowered or reduced 

 sometimes even to two flowers ; fruitlets rather large, 

 considerably compressed. H. Asiatica. 



Leaves crenate or lobed 1222 



