2772 



POTENTILLA 



POTENTILLA 



soil. P. tridentata is an attractive evergreen species 

 forming thick mats. It does well in any fairly rich soil 

 in open or partially shaded positions. Potentillas are 

 ptopagated by division or seed, the hybrids only by 

 division. P. fruticosa may be increased by greenwood 

 cuttings. (F. W. Barclay.) 



Hybrid potentillas (Fig. 3157) have nearly all the 

 good qualities in a border plant, handsome foliage 

 and free-blooming habit. They continue in bloom from 

 spring until autumn, although most profusely in June 

 and July. They cannot be said to be reliably hardy in 

 the latitude of Boston, probably not above Washington. 

 They do not grow over 2 feet and seldom need staking. 

 A heavy soil suits them best. Choice varieties are propa- 

 gated by division of the rootstock in spring; cuttings 

 will not root. They run mostly in shades of maroon, 

 scarlet, and orange, often beautifully banded with 

 yellow. They bear seed freely, and when carefully 

 hybridized one may get a very fine strain with a good 

 proportion of double blooms. Seedlings bloom the 

 second year. Some of the species make neat rock-plants, 

 especially P. tridentata, P. verna, and P. argentea, 

 the last, though common, is valuable in places in which 

 other plants will not grow. (T. D. Hatfield.) 



alba, 9. 

 albicans, 1 

 alpestris, 27. 

 ambigua, 5. 

 Anserina, 31. 

 argentea, 21. 

 arguta, 11. 

 argyrophylla, 18. 

 atrosanguinea, 19. 

 calabra, 21. 

 canadensis, 30. 

 cinerea, 29. 

 dahurica, 1. 

 dubia, 26. 

 eriocarpa, 6. 



INDEX. 



formosa, 15. 

 Friedricksenii, 1. 

 fruticosa, 1. 

 glandulosa, 12. 

 Gordonii, 33. 

 gracilis, 14. 

 grandiflora, 24. 

 hsematochrus, 17. 

 Hippiana, 13. 

 insignis, 18. 

 laciniata, 23. 

 laciniosa, 23. 

 nepalensis, 15. 

 nitida, 8. 

 pacifica, 32. 



palustris, 3. 

 pyrenaica, 25. 

 recta, 22. 

 rupestris, 10. 

 Salcsoviana, 2. 

 speciosa, 7. 

 sulphurea, 22. 

 Thurberi, 16. 

 Tonguei, 15. 

 tridentata, 4. 

 Veitchii, 1. 

 verna, 28. 

 villosa, 20. 

 Vilmoriniana, 1. 



ARTIFICIAL KEY TO THE SPECIES. 



A. St. distinctly shrubby, diffusely 



branched 1. fruticosa 



AA. St. herbaceous or merely suffruticose. 

 B. Basal Ivs. pinnate, 5-7-foliolate. 

 c. Lvs. white-tomentose, at least be- 

 neath. 

 D. Fls. cymose: Ifts. whitened both 



sides 13. Hippiana 



DD. Fls. lateral, solitary at the nodes: 



Ifts. usually green above. 

 E. Carpels dorsally furrowed: 

 peduncles and sts. pilose; 



tomentum lustrous 31. Anserina 



EE. Carpels dorsally rounded: 

 peduncles and sts. glabrate; 



tomentum dull 32. pacifica 



cc. Lvs. green both sides. 



D. Fls. white, rose, or dark purple; 

 infl. more or less lax, diffusely 

 cymose; petals exceeding the 



E. Lfts. round-elliptic or rhom- 

 bic-ovate: carpels glabrous, 

 smooth or rugulose: inft. 



glandular 10. rupestris 



EE. Lfts. oblong or cuneate-oblong 

 or oblong-lanceolate: infl. 

 not glandular. 



F. Carpels densely pilose: pet- 

 als large, obovate, showy. 2. Salesoviana 

 FF. Carpels glabrous: petals 



minute, ovate-lanceolate . 3. palustris 

 DD. Fls. creamy yellow; infl. con- 

 gested; petals not longer than 



the sepals 11. arguta 



ODD. Fls. bright yellow. 



E. Lfts. minute, ^-^in. long, 

 dissected: petals shorter than 



the sepals 33. Gordonii 



EE. Lfts. large, 1 in. long or more, 



dentate or incised 12. glandulosa 



BB. Basal Ivs. palmately 5-7-foliolate. 

 c. Fls. white: Ivs. white-silky or glau- 

 cous beneath 9. alba 



cc. Fls. yellow. 



D. Lvs. white-woolly or white stel- 

 late-canescent, at least beneath. 

 E. Caudex with abundant rooting 

 stolons: sts. scarcely exceed- 

 ing the basal Ivs., pilose 

 with long horizontal yellow- 

 ish hairs: Ivs. canescent... .29. cinerea 

 EE. Caudex without stolons: sts. 

 much exceeding the Ivs., 

 without the above hairs. 

 F. St. 16-28 in. high: fls. 



7-9 lines broad 14. gracilis 



FF. St. 6-16 in. high: fls. 4-7 



lines broad 21. argentea 



DD. Lvs. green beneath, or somewhat 



silky. 

 E. Fls. lateral, solitary at each 



node 30. canadensis 



EE. Fls. terminal and solitary or 



cymose. 

 F. Lfts. large, 2-6 in. long: 



plants large. 



G. Infl. glandular: Its. ru- 

 gose, coarsely serrate- 

 dentate 22. recta 



GO. Infl. glandless: Irs. not 

 rugose, laciniate-pin- 



natifid 23. laciniosa 



FF. Lfts. small, l /r~l l /t in- 

 long: plants low. 

 G. Style conical: fls. 1 in. 



broad 25. pyrenaica 



GG. Style clavate: fls. 5-12 



lines broad. 



H. Stipules of basal Ivs. 

 broadly ovate or 

 ovate-lanceolate: sto- 

 lons scarcely elon- 

 gated, clothed with 



dead stipules 27. alpestris 



HH. Stipules of basal Ivs. 

 linear, elongated: 

 stolons much elonga- 

 ted, rooting, not 

 clothed with dead 



stipules 28. verna 



ccc. Fls. purple or rose. 



D. Lvs. and sts. velvety with yellow- 

 ish hairs: Ivs. almost tomen- 



tose beneath 17. haematochrus 



DD. Lvs. and sts. not yellowish 



hairy: Ivs. green both sides. 

 E. Lfts. 5: petals clear purple 

 with dark veins and dark 

 spot at base: infl. not 



glandular 15. nepalensis 



EE. Lfts. mostly 7: petals dark 



purple: infl. glandular 16. Thurberi 



BB. Basal Ivs. palmately, or rarely pin- 



nately, 3-foliolate. 



c. Fls. rose, white, or creamy white. 

 D. Lfts. glabrous, or slightly stri- 

 gose beneath, 3-toothed: fls. 



white 4. tridentata 



DD. Lfts. white-silky on both sides, 

 3-toothed or entire: fls. rose, 



rarely white 8. nitida 



DDD. Lvs. tomentose at least beneath; 



teeth several. 



E. Petals white or cream, nar- 

 row, cochleate, and dorsally 



villous 7. speciosa 



EE. Petals purple or red, broadly 



obovate, glabrous 19. atrosanguinea 



cc. Fls. yellow. 



D. Lvs. white-tomentose beneath, 

 white-silky above (see also P. 

 grandiflora). 

 E. Margin of Ifts. incised-ser- 



rate: fls. 1-1 ]4 in. broad. . 18. argyrophylla 

 EE. Margin of Ifts. crenate-ser- 



rate: fls. %-l in. broad 20. villosa 



