25 S 



ROSACEAE. 



VOL. II. 



8. ARGENTINA Lam. Fl. Franc. 3: 118. 1778. 



Perennial herbs, with slender stolons, interruptedly pinnate leaves, the flowers solitary, 

 axillary, peduncled. Calyx-tube short and broad. Bractlets, sepals and petals 5, or often 

 more. Petals yellow, not clawed. Stamens 20-25, borne around the base of the hemi- 

 spheric receptacle; filaments filiform. Pistils numerous on the receptacle; style lateral, 

 filiform. Achenes with thick pericarp. Seeds ascending, amphitropous. [Latin, referring 

 to the silvery white pubescence of the under side of the leaves.] 



About 8 species, natives of the north temperate and subarctic zones. Besides the following, 

 4 others occur in western North America. Type species : Argentina vulgaris Lam. 



i. Argentina Anserina (L.) Rydb. Silver-weed. Wild or Goose-tansy. Fig. 2249. 



Potentilla Anserina L. Sp. PI. 495. 1753. 



Argentina vulgaris Lam. Fl. Franc. 3: 119. 1778. 



A. Anserina Rydb. Mem. Dept. Bot. Col. Univ. 2 : 159. 1898. 



A. Dabcockiana Rydb. N. Am. Fl. 22: 354. 1908. 



A. litoralis Rydb. loc. cit. 1908. 



Herbaceous, tufted, spreading by slender runners 

 i-3 long. Stipules membranous; leaves petioled, 

 pinnate, 3'-i8' long; leaflets 7-25, oblong, oblanceolate 

 or obovate, obtuse, the lower generally smaller, often 

 with still smaller ones interspersed, all sharply serrate, 

 nearly glabrous above, white or silky-pubescent be- 

 neath; peduncles axillary, solitary, slender, erect, i- 

 flowered, about equalling the leaves; flower yellow, 

 8"-i2" broad ; petals broadly oval or obovate, entire or 

 emarginate, exceeding the ovate acute calyx-lobes and 

 oval bractlets ; stamens about 20; style filiform, lateral; 

 receptacle villous; achenes grooved or grooveless. 



On shores and salt meadows, New Jersey to Greenland, 

 west to Nebraska, British Columbia and Alaska, south in 

 the Rocky Mountains to New Mexico and to California. 

 Also in Europe and Asia. Argentina. Silver-feather. Dog's- 

 tansy. Goose-grass. May-Sept. Consists of several or 

 numerous races, differing in size, in shape of the leaflets, 

 and slightly in the achenes ; small northern plants have 

 been referred to A. Egedii of Greenland. 



9. COMARUM L. Sp. PI. 502. 1753. 



A stout dark green nearly glabrous herb, with alternate pinnate large-stipuled leaves, the 

 large red or purple flowers cymose or solitary, terminal or also axillary. Calyx deeply 5-lobed, 

 5-bracteolate, the bractlets narrow. Petals shorter than the calyx-lobes, acute, purple. 

 Stamens numerous, inserted on the large pubescent disk. Pistils numerous, inserted on the 

 somewhat enlarged, pubescent receptacle which becomes spongy in fruit. Style lateral. 

 Achenes glabrous. Seed pendulous. [Greek name of the Arbutus, from the similar fruits.] 



A monotypic genus of the north temperate zone. 



i. Comarum palustre L. Purple or Marsh 

 Cinquefoil. Purple Marshlocks. Cow- 

 berry. Purplewort. Fig. 2250. 



Comarum palustre L. Sp. PI. 502. 1753. 



Potentilla palustris Scop. Fl. Carn. Ed. 2, i: 359. 1772. 



Decumbent and somewhat woody at the base, the 

 upper part of the stems pubescent. Leaves pinnate, 

 the lower long-petioled, 5-7-foliolate; leaflets ob- 

 long or oval, sharply or incisely serrate, obtuse or 

 acutish at the apex, narrowed at the base, i'~3' long; 

 stipules membranous, sometimes adnate to the peti- 

 ole for half its length ; upper leaves nearly sessile, 

 3-5-foliolate ; flowers showy, 9"-i5" broad ; calyx- 

 lobes red or purple within, ovate, acuminate, much 

 exceeding the ovate-lanceolate petals ; bractlets much 

 shorter than the calyx-lobes ; disk lobed. 



In swamps and peat-bogs. Greenland and Labrador to 

 New Jersey, Iowa, British Columbia, Wyoming, Alaska 

 and California. Northern Europe and Asia. Marsh 

 five-finger. Meadow-nuts. Bog-strawberry. June-Aug. 



