EOSACEAE 521 



11. POTENTILLA L. 



Herbs or shrubby plants, with erect or creeping stems. Leaves alternate : blades pin- 

 Tiately or digitately divided. Flowers perfect, in terminal corymbose cymes or solitary and 

 axillary to leaf-like bracts. Calyx erect or drooping. Sepals usually 5, persistent. Bract- 

 lets 5. Petals usually 5, white, yellow, red or purple, mostly sessile. Stamens mostly 20 

 (5-30) in 2 or 3 series. Receptacle hemispheric or conic. Pistils mostly numerous : style 

 terminal. Ovule pendulous, anatropous. Achenes smooth or wrinkled. CiNquEFOll,. 



Flowers axillary to the leaf-like bracts : stems creeping or spreading : perennials. 

 Stems silky-villous : first flower at the second node of the stem or a succeeding 



node. 1. P. Canadensis. 



Stems silky-strigillose : first flower at the first node of the stem. 2. P. pumila. 



Flowers in terminal cymes : stems erect or ascending : annuals or biennials. 

 Upper leaf-blades digitately 3-7-foliolate. 



Corolla 10 mm. broad : stamens 20 : petals as long as the sepals. 3. P. Monspeliensis. 



Corolla 5 mm. broad : stamens 5-8 : petals much shorter than the sepals. 4. P. penlandra. 



Upper leaf-blades pinnately 3-11-foliolate. 5. P. jiaradoxa. 



1. Potentilla Canadensis L. Perennial, bright green. Stems branched at the base, 



the branches 3-6 dm. long, becoming decumbent or prostrate, silky-villous : basal leaves 



few ; petioles 4-6 cm. long, silky ; blades digitately 5-foliolate, or 3-foliolate with the 



latei'al leaflets nearly divided ; blades of the leaflets obovate or cuneate-oblong, 2-4 cm. 



long, coarsely and usually doubly serrate : stem-leaves similar to the basal but with shorter 



petioles : flowers solitary in the axils : pedicels 3-10 cm. long : sepals ovate or lanceolate, 



about as long as the lanceolate bractlets : corolla yellow, 10-12 mm. broad : petals obcor- 



date, about J longer than the sepals : achenes with a few transverse wrinkles. 



In dry soil, Maine to Quebec, Minnesota, northern Georgia and the Indian Territory. Spring and 

 summer. — A larger form with more elongated branches, more appressed pubescence and glabrate 

 larger leaflets .5-6 cm. long, is P. Canadensis simplex (Michx.) T. & G. 



2. Potentilla pumila Poir. Perennial, pale green. Stems erect, less than 1.5 dm. 

 tall, producing elongated runner-like densely silky-strigillose branches : basal leaves few; 

 petioles 2-4 cm. long, pubescent like the stem ; blades digitately 5-foliolate : blades of the 

 leaflets obovate, about 2 cm. long, coarsely serrate : stem-leaves similar to the basal, but 

 witli shorter petioles : flowers solitary in the axils, the first one accompanying the first 

 stem-leaf: pedicels 3-5 cm. long : sepals lanceolate, about as long as the similar bractlets : 

 corolla yellow, 6-10 mm. broad : petals obcordate, little surpassing the sepals. 



In dry woods, New England to North Carolina and Georgia. Spring. 



3. Potentilla Monspeliensis L. Annual or biennial. Stems solitary or several to- 

 gether, 3-8 dm. tall, branched above, hirsute : leaf-blades digitately 3-foliolate (or the 

 lower ones in robust plants digitately or pinnately 5-foliolate): stipules ovate, 1-4 cm. 

 long, toothed ; blades of the leaflets obovate, 3-10 cm. long, serrate with broad teeth : hy- 

 panthium hirsute, becoming 1 cm. broad : sepals oblong-lanceolate, acute, about as long as 

 the similar bractlets : corolla light yellow, about 1 cm. broad : petals obovate, almost as 

 long as the sepals : stamens 20. 



In dry soil and cultivated grounds, Labrador to Alaska, Georgia, Texas and Mexico. Spring and ■ 

 summer. Also in Europe and Asia.— The form with oblong leaflets and line pubescence, rarely with 

 some longer hairs, is P. Monspeliensis Norvdgica (L.) Rydb. 



4. Potentilla pentandra Engelm. Annual or biennial. Stems 3-7 dm. tall, hirsute, 

 much branched above : blades of the basal and lower .stem-leaves 3-foliolate, with the lower 

 pair of leaflets parted so as to simulate a 5-foliolate blade, slender-petioled ; blades of the 

 leaflets oblanceolate or oblong, 3-5 cm. long, obtuse, incised-dentate : cyme flat-topped : 

 sepals ovate, acute : corolla pale yellow, less than 5 mm. broad : petals spatulate, much 

 surpassed by the sepals : stamens 5-8. 



On prairies, Manitoba to Missouri, Kansas and Arkansas. Summer. 



5. Potentilla paradoxa Nutt. Annual or biennial. Stems 3-8 dm. tall, softly 

 pubescent, rather much branched: blades of the lower leaves pinnately 7-11-foliolate ; 

 blades of tlie leaflets obovate or oval, 1.5-2.5 cm. long, obtuse, sparingly pubescent: 

 cymes loose : sepals ovate, acute : corolla 7-8 mm. broad : petals obovate-cuneate, about as 

 long as the sepals : stamens about 20. 



On river banks or in low grounds, New York to Ontario, Oregon, Tennessee and Mexico. Summer. 



12. WALDSTEINIA Willd. 



Perennial acaulescent herbs, resembling Fragariae, with horizontal rootstocks. Leaves 



basal, with long petioles : blades simple, 3-5-lobed or 3-5-foliolate, the lobes or leaflets 



with toothed or incised blades : stipules membranous. Scapes erect, branched above. 



Flowers perfect, in terminal corymbs. Hypanthium turbinate. Sepals 5, valvate, often 



