ROSACEA. 



359 



&c. In others the stems and branches are slender and spread along 

 the ground (fig. 420), or form runners, just as in the Strawberries. 

 The leaves are very variable in form, for besides the exceptional forms 

 of the degenerated types that we shall unite to the genus 'Poteniilla, 

 there are species with imparipinnate leaves, and others with digitate 

 leaves, as indicated by the generic name Baciylophylluin} 



There are Potentils in whicli the androceum is reduced to fifteen, 

 ten, or even five stamens. Take for instance the American plants, 

 of which it has been proposed to make the genera Ilurkelid- and 



Potentilla (ITorJcelia) congesta. 



Fig. 421. 

 Flower. 



Fig. 422. 

 Longitndinal section of flower. 



Ivesia^ : L santolinoidcs^ has fifteen stamens; //. conycsfa' cimeata,^ 

 tridentatd' have ten — five superposed to the sepals, five to the petals. 

 H. Gordoni^ has only five, superposed to the sepals. In the Ilorkelias 

 and Ivesias first known, this character, not of sufficient value in 

 itself, was accompanied by others which then justified the establish- 

 ment of new^ generic divisions ; but they have been found not to be 

 constant in the species more recently studied, and can only serve to 

 mark out secondary divisions in the genus Potentilla. These characters 



' Spenn., Fl. Frihiirg., iii. 1034 (P. procum- 

 bens Clairy., ex DC, Prodr., ii. 587 ; — Sihhal- 

 dia procumbens L., Spec., 406). 



■■^ Cham. & Sciiitl,, Liuncea, ii. 26. — Toke. 

 &CTn.,Fl. N. Amer., i. 434. — Hook., Pot. Mag., 

 t. 2880.— LiNDi., Bot. Reg., t. 1997.— Endl., 

 Gen., n. 6364.— Tohe. & Gr., ap. Wippl., 164, 

 t. 6. — A. Geat, Proceed. Amer. Acad., vi. 528; 

 vii. 336.— B. H., Gen., 621. 



•' Tore., ap. Wippl., ii. t. 4.— Toee. & Ge., 

 Bot. Pacif. Fxp., vi. 72.— A. Geat, Proceed. 

 Amer. Acad., vi. 530; vii. 337. 



•* A. Gray, Ioc cit., 531. — I. gracilis Tore. 

 & Ge., Netfb. Pep., 1. 11. — Potentilla Newberryi 

 A. Gray, Ioc. cit. 



* Hook., Bot. Mag., Ioc. cit. 



" LiNBL., Ioc. cit. (JI. californica Cir. & 

 ScMLTL., Linncea, Ioc. cit., nee aliorum). — II. 

 grandis HooK. & Abn. — H. capitata Tore. ap. 

 VViPPL., Ioc. cit. (nee Lindl.). 



^ ToRR., ap. VVippL., Ioc. cit. 



8 Hook., Jlook. Journ., v. 341, t. VI.— If. 

 millefoUata ToEB. — Ivesia Gordoni ToRU. &, 

 Gr., ap. NnwH., 6, 72. 



