POTENTILLA 



POTENTILLA 



1421 



north temperate and frigid zones, and characterized by 

 their compound leaves, 5 bracteoles borne at the base of 

 the 5 sepals, which in turn are borne upon the edge of 

 a cup-shaped, dry receptacle; stamens 10-30, together 

 with the 5 rounded petals inserted upon the margin of 

 the receptacle: pistils many, in fruit becoming minute 

 akenes; styles deciduous. Those in cultivation are all 

 hardy perennial plants suitable for border planting. 

 The most valuable double-fid, forms are hybrids 



K. M. WIEGAND. 



The American Potentillas are generally rather un- 

 attractive plants with small flowers. They are, as a 

 rule, very tenacious of life and do well with ordinary 

 care. P. fruticosa, a handsome and distinct low shrub, 

 prefers moist positions, but will grow in even very 

 dry soil. Where thoroughly established in moist soil it 

 is difficult to eradicate. P. argentea should be given a 

 dry soil, preferably about rocks. It is tenacious of life 

 and is quite attractive. P. Hippiana, a western species 

 with comparatively large foliage of decided gray color, 

 is hardy east. It is a good perennial preferring dryish 

 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 

 prop, by division or seed, the hybrids only by division. 

 P. fruticosa may be increased by greenwood cuttings. 



F. W. BARCLAY. 



Hybrid Potentillas have nearly all the good qualities 

 we look for 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 two feet and seldom need stak- 

 ing. A heavy soil suits them best. Choice varieties are 

 propagated by division of the rootstock in spring; cut- 

 tings 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 we may get a very fine strain with a good 

 proportion of double ones. Seedlings bloom the second 

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

 pecially 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. 



1. fruticdsa, Linn. Fig. 1935. Much-branched, 5 in. 

 to 4 ft. high, with peculiar shreddy bark: Ivs. all pin- 

 nate; Ifts. 3-7, small (6-12 lines long), oblong-linear, 

 acute, silky with revolute margins: fls. numerous, 

 bright yellow, showy, 8-16 lines broad; style lateral: 

 akenes, receptacle and disk all long-hairy. Swamps and 



Basal leaves pinnate. 



B. Stem shrubby 1. fruticosa 



B. Stem herbaceous. 



c. Lvs. silky, tomentose beneath. 2. Hippiana 

 CC. Lvs. green on both sides. 



D. Lfts. large, 1 in. long, den- 

 tate 3. glandulosa 



4. rupestris 

 DD. Lfts. minute, %-% in. long, 



much divided 5. Gordon! 



Basal Ivs. palmately 8-7-foliolate. 

 B. Lfts. S. 



c. Fls. white 6. tridentata 



cc. Fls. yellow or red 7. grandiflora 



8. argyrophylla 



B. Lfts. 5-7 9. Nepalensis 



c. Fls. red or purple 10. Thurberi 



cc. Fls. yellow. 11. verna 



D. Lvs. green beneath 12. Pyrenaica 



13. laciniosa 



14. gracilis 

 DD. Lvs. white beneath 15. argentea 



1935. Potentilla fruticosa (X %). 



rocky places, N. Amer., Eu., Asia. J. H. III. 31:602. 

 D. 121. A useful shrub, flowering throughout the 

 summer. 



2. Hippiana, Lehm. Stem erect, stout, 1-2 ft. high, 

 silky, erect-branched above; stipules large, ovate- 

 lanceolate, subentire: basal Ivs. rather large ; Ifts. 3-5 

 pairs, whitish silky above, tomentose beneath, decreas- 

 ing in size toward base of leaf, obovate-cuneate, 1-2% in. 

 long, obtusely toothed ; cauline Ivs. several and similar: 

 fls. deep yellow, %-l in. broad, cymose; bracteoles 

 nearly equaling the calyx, acute; petals slightly ex- 

 ceeding the sepals, retuse. Western America. 



3. glanduldsa, Lindl. Strict, 1-2 ft. high, slender, 

 viscid and glandular-hairy, erect, branched above: Ivs. 

 mostly basal, 4-6 in. long; Ifts. 3-4 pairs, 1-1 % in. long, 

 obovate, obtusish, coarsely serrate-dentate, nearly gla- 

 brous; cauline Ivs. 3-parted : fls. rather large, yellow 

 petals entire, equaling the long-acuminate sepals; styles 

 thickened below, inserted at base of carpel: akenes 

 glabrous. Western U. S.; grows well in dry, sterile 

 ground. 



4. rup6stris, Linn. Very similar to the last, slightly 

 stouter: fls. larger, nearly white; petals entire, much 

 exceeding the calyx. June, July. Eu. Grows well in 

 dry, sterile soil. 



5. G6rdoni, Baill. (Ivesia G6rdoni, Torr. & Gray). 

 Root stout: caudex woody and cespitose: stems erect, 

 4-12 in. high, and, like the Ivs., glandular - pubescent 

 or glabrous: Ivs. mostly basal, numerous; Ifts. 10-20 

 crowded pairs; cauline Ivs. few, very small: fls. small 

 and inconspicuous in a crowded cyme; petals yellow, 

 spatulate, shorter than the sepals; stamens only 5; pis- 

 tils 1-5. Western U. S. ; forms dense mats in dry soil. 

 Possibly generically distinct. 



6. tridentata, Soland. Often woody at the base, 1-12 

 in. high, slender: branches erect-spreading, appressed- 

 pubescent: Ivs. mostly basal, long-petioled ; Ifts. %-l 

 in. long, oblanceolate, truncate and 2-5-toothed at the 

 apex, cuneate and entire below, coriaceous, dark green, 

 paler beneath: fls. several, small, 3-5 lines broad, in a 

 terminal, nearly naked cyme; petals oval, entire, ex- 

 ceeding the calyx; style lateral, filiform: akenes and 

 receptacle villous. June, July. Northern N. Amer., 

 Greenland, Scotland. Good for dry banks and rockeries. 



