542 Rydberg : Species from Western United States 



leaflets which are 2-3 cm. long and about 2 mm. wide, glabrous 

 above and slightly strigose beneath ; raceme with a 1-2 dm. long 

 peduncle, rather lax and few-flowered ; flowers almost sessile, about 

 12 mm. long ; calyx about 7 mm. long, strigose with dark hairs ; 

 lobes short, lanceolate and unequal ; corolla yellow ; pod with a 

 stipe which is about i cm. long and curv^ed upwards, upright, ob- 

 long, obcordate in cross-section, with the dorsal suture strongly 

 inflexed to about half-way to the ventral one, subcoriaceous, the 

 body being about 2 cm. long. 



The specimens were named A. arrcctns Gray ?, to which species 

 it has a superficial resemblance, differing in the pod, the struc- 

 ture of which places it near A. Drununondii and A. scopulonmi. 

 From these it differs, however, in the short erect pod. It grows 

 on dry hillsides. 



Oregon: Malheur, 1885, W. C. Ciisick, I2j8 (Gray Herba- 

 rium). 



Potentilla rosulata 



Glandular and viscid pubescent throughout ; caudex thick and 

 lignose, topped with dense rosettes of leaves and short stems ; the 

 latter, at least in the type specimens, less than i dm. high ; basal 

 leaves 4—5 cm. long, long-petioled, pinnately 5-foliolate ; stem- 

 leaves ternate, short-petioled, or the upper subsessile ; lower 

 stipules lanceolate and thin ; the upper ovate and rather thick ; 

 leaflets thick, densely viscid and glandular pubescent, broadly 

 obovate, or the terminal orbicular, deeply crenate, or somewhat 

 cleft, 7-10 mm. long; pedicels 5-15 mm. long; hypanthium 

 about 5 mm. in diameter, densely viscid pubescent ; bractlets 

 ovate, about half as long as the broadly triangular ovate acute or 

 acuminate sepals ; petals small, oblong, whitish or light yellow, 

 about as long as the bractlets ; stamens between 30 and 40 ; 

 anthers decidedly didymous ; pistils 20-40 ; style filiform, at- 

 tached near the apex of the ovary. 



This is nearest related to Potentilla saxosa Greene,* but differs 

 in the less numerous leaflets of the basal leaves, the much thicker 

 and less incised leaflets, the shorter and stouter stems, the smaller 



* In my monograph I transferred this species to Horkelia, on account of its close 

 resemblance to Horkelia Baileyi, but a study of better material in Mr. T. S. Bran- 

 degee's herbarium has persuaded me that I made a mistake. The species is a true 

 Potentilla. There are three species, all belonging to the Poteittilleae, that are almost 

 identical in the vegetative parts, but still must be placed in three different genera. 

 These are : Potentilla saxosa Greene, Horkelia Baileyi Wats., and Purpiisia saxosa 

 Brandegee. 



