22 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 



Leaves not at all tomentose. 



Style subterminal. 8. Aureae. 



Style attached below the apex of the achene. 17. Brevifoliae. 



Leaves with 3-13 pairs of leaflets. 

 Leaves green on both sides. 



Petals yellow ; bristles of the receptacle not unusually 



long. 18. MuUijugae. 



Petals white ; bristles of the receptacle very long. 19. Afenicolae. 



Leaves grayish or whitish silky, or tomentose, at least be- 

 neath. 



Leaflets toothed or incised. 20. Leucophyllae. 



Leaflets dissected into linear segments. 21. Candicantes. 



§ I. HAEMATOCHRI. 



Petals dark red or dark purple, broadly obcordate, rather large and showy ; stamens 

 mostly 20, in 3 series on the very thick and swollen, red or purple margin of the disk, 

 the antisepalous stamens generally larger and with thicker filaments. 



The group consists of two species growing in southwestern United States and north- 

 ern Mexico, four in Mexico, and a few in India, among others P. Nepalensis and P. 

 atrosanguinea, which are sometimes cultivated. 



Leaves digitate. 



Leaves glabrate, without tomentum. 1. P. Tliurheri. 

 Leaves glabrate or appressed silky above, more or less white tomentose beneath. 



Leaflets obovate to oblanceolate, serrate. 2. P. atrorubens. 



Leaflets oblong, crenate above the middle. 3. P. fusea. 



Leaflets oblong, entire margined, 3-toothed at the apex. 4. P. comarioides. 



Leaves softly velutinous on both sides. 5. p. Haematoehrus. 



Leaves pinnate with approximate leaflets. 6. P. Ehrenberqiana. 



§ 2. TORMENTILLAE. 



Plants perennial with a more or less prostrate or spreading stem, often rooting at the 

 nodes. Leaves digitately 3-5-foliolate. Flowers middle-sized, borne on long solitary 

 axillary pedicels. Petals 4 or 5, obcordate, yellow, surpassing the sepals by about one half 

 Stamens 16-20, with rather short filaments. Pistils numerous ; style slender, filiform. 



The original Tormentilla had 4-merous flowers, but sometimes, however, they are 

 5-merous, and other species that have regularly 5-merous flowers have no other charac- 

 ter which would warrant the division into two groups, much less into two genera. The 

 group is mainly European, only three species being natives of North America. 



