410 ROSACEAE 



Leaves densely yellowish silky above, snow-white, tomentose and silky beneath. 



14. P. Candida. 

 Leaves green and sparingly silky above, tomentose, but neither snow-white nor 

 silky beneath. 15. P. Pecten. 



Pubescence of the petioles and stem spreading. 16. P. Bakeri. 



IV. Pectinisectae. 



Leaves green, finely silky beneath, slightly if at all tomentose. 17. P. pectinisecta. 

 Leaves wliite-tomentose beneath. 



Divisions of the leaflets scarcely revolute; petals 7-10 mm. long. 



Leaves loosely villous-tonaentose above. 18. P. longiloba. 



Leaves appressed-silky above. 19. P. Bldschkeana. 



Divisions of the leaflets narrowly Linear, revolute; petals 5-7 mm. long. 



20. P. flabelliformis. 

 V. Graciles. 



Leaflets cut-toothed or cleft with lanceolate teeth. 



Leaflets with a cuneate entire base; tomentum sparse. 21. P. intermitiens. 



Leaflets toothed or cleft along cheir whole margins. 

 Petioles with appressed or ascending hairs. 



Stem slender, 3-5 dm. high; inflorescence open, scarcely leafy. 



22. P. viridescens. 

 Stem stout, 4—7 dm. high, erect, leafy as well as the inflorescence. 



Leaves grayish green beneath, only slightly tomentose. 



23. P. olomerata. 

 Leaves densely white-tomentose beneath; stem densely hairy. 



24. P. dichroa. 

 Petioles with spreading hairs. 



Leaflets of at least the stem-leaves oblanceolate, sparingly hairy or glabrate 

 above; petals often 1 cm. long. 25. P. gracilis. 



Leaflets obovate, densely hairy above; plant 3-4 dm. Mgh; petals 5-6 mm. 

 long. 26. P. camporum. 



Leaflets merely crenate with rounded or ovate teeth. 27. P. filipes. 



VI. SUBJUGAE. 



One species. 28. P. subjuga. 



VII. AXJREAE. 



Leaflets toothed, the toothing not deeper than half-way to the midrib. 

 Leaflets crenate with rounded or rounded-ovate, obtuse teeth. 



29. P. Vreelandii. 

 Leaflets closely toothed or cleft with lanceolate or oblong, acute or barely obtusish 

 teeth or segments. 

 Leaflets spatulate or obovate; teeth usually spreading. 35. P. concinnaeformis. 

 Leaflets cimeate or cuneate-oblanceolate, tootlied above the middle, teeth ascend- 

 ing. 

 Leaves rather densely silky-strigose, the basal ones often inclined to be pin- 

 nate. 30. P. diversifolia. 

 Leaves slightly pubescent, in age glabrous and somewhat glaucous, digitate. 



31. P. glaiicophylla. 

 Leaflets cleft or divided, the divisions extending two-tliirds to the midrib or further. 



Leaflets cleft into oblong or lanceolate divisions, slightly silky-strigose, in age glabrate. 



32. P. perdissecta. 

 Leaflets divided into linear divisions, permanently strigose. 33. P. muUisecta. 



VIII. CONCINNAE. 



Leaflets densely silvery-silky on both sides, only sUghtly if at all tomentose beneath. 

 Leaflets deeply dissected. 15. P. Pecten. 



Leaflet .s luci'fly toothed. 



IiitloiM scciice many-flowered and dense. 34. P. fastigiata. 



Inllorcsciiicc few-flowered and open. 35. P. concinnaeformis. 



Leaflets (Icn.sclj white-tomentose beneath. 

 LeaHfts nicrcly crenate or serrate. 



Leaflets obovate to oblanceolate, toothed except at the very base. 



Sepals ovate, acute. 36. P. concinna. 



Sepals lanceolate, acuminate. 



Leaflets obovate, few-toothed. (Occasional forms of) 42. P. nivea. 

 Leaflets oblanceolate, many-toothed. (Depauperate forms of) 



27. P. filipes. 

 Leaflets oblong, with entire margins, only 3-toothed (seldom 5-toothed) at the 

 apex. 37. P. bicrenata. 



Leaflets deeply dissected. 



Bractlets lanceolate or linear-lanceolate, acute; petals light yellow. 

 Plant diffuse; sepals ovate; leaves more or less grayish above. 



38. P. divisa. 

 Plant erect or ascending; sepals lanceolate, acuminate; leaves green above. 



39. P. quinqucfolia. 

 Bractlets linear, obtuse; petals 4 mm. long, golden- yellow ; inflorescence rather 



dense. 40. P. modesla. 



