184 ROSACEA. Ivesia. 



In the Sierra Nevada, from Mt. Brewer {Brewer) and Mt. Pinos (Kolhroclc) to Lake Tahoe, 

 Lemrnon. 



7. I. gracilis, Ton. & Gray. Canescently villous with spreading hairs : stems 

 slender, a span high, from an apparently annual or biennial root : leaflets 5 to 1 

 pairs, scattered on the slender rhachis, 3 - 5-parted with oblong segments, 2 to 4 lines 

 long : flowers on elongated pedicels in a very diffuse panicle : calyx nearly 2 lines 

 long, broadly campanulate ; hractlets nearly equalling the lobes : petals white, 

 obovate, as long as the calyx : stamens 15 or 20 : carpels numerous : akenes rugose. 

 — Pacif. E. Bep. vi. 72, t. 11. Poterdilla Neivberryi, Gray, 1. c. 532. 



On the banks of Rhett Lake, Newberry. A species peculiar in its annual or biennial root and 

 in the large number of its carpels. 



8. I. Baileyi, Watson. Viscidly pubescent : stems slender, 6 inches high : leaf- 

 lets 3 to 10 pairs, cuneate-obovate, 3- 7-toothed or parted : flowers on slender pedi- 

 cels in a diffuse panicle : calyx 1-| lines long, exceeding the yellow spatulate petals: 

 stamens 5 : carpels 1 to 5. — Bot. King Exp. 90. 



Var. setosa, Watson, 1. c. Leaflets all parted, the lobes setosely tipped : more 

 gland ular-hairy . 



West Humboldt Mountains, Nevada (Bailey) ; the variety in the East Humboldt Mountains, 

 Watson. The remaining species also belong to this group. 



I. Kingii, Watson, 1. c. 91. Glabrous throughout : stems a span long or more : leaflets numer- 

 ous, entire or 2 - 3-parted, the lobes rounded, a line long : flowers on slender pedicels in an open 

 panicle : calyx 2 lines long, shorter than the white orbicular petals : stamens 15 or 20 : carpels 



5 to 8. — Valleys of Northeastern Nevada, in alkaline soil, Watson. 



I. depauperata, Gray in herb. Sparingly pubescent : stems erect, a foot high or more : leaf- 

 lets numerous, cuneate-obovate or oblong, deeply 2 - 3-cleft : flowers pedieelled, in a rather open 

 panicle : calyx 2 or 3 lines long, purple within, exceeding the linear dark-purple petals : stamens 

 5, purple : carpels 2. — Potentiila depauperata, Engelm. ; Gray, Proc. Am. Acad. vii. 399. San 

 Francisco Mts., Arizona, Anderson, Palmer, Loew. The only purple-flowered species. 



18. ADENOSTOMA, Hook. & Am. Chamiso. 



Calyx persistent, 5-lobed, calyculate ; tube obconical, 10-ribbed; lobes membra- 

 naceous, broad. Petals 5, orbicular, spreading. Stamens 10 to 15, usually 2 or 3 

 together between the petals. Ovary simple, obliquely obovoid, the oblique or trun- 

 cate summit pubescent : style lateral, curved, with an obliquely dilated stigma : 

 ovules 1 or 2, suspended. Fruit a membranaceous akene, coriaceous at the summit, 

 included in the indurated calyx-tube. Seeds unknown. — Evergreen shrubs, some- 

 what resinous ; leaves thick and coriaceous, small and numerous, entire, solitary and 

 rarely opposite, or fascicled ; stipules small ; flowers small, white, shortly peduncu- 

 late in terminal racemose panicles. 



1. A. fasciculatum, Hook. & Arn. A diffusely branched shrub, 2 to 20 feet 

 high, with reddish virgate branches, and grayish bark becoming shreddy : leaves 

 fascicled, linear-subulate, 2 to 4 lines long, acute, usually channelled on one side, 

 smooth and often resinous, rarely lobed above ; stipules small, acute : flowers nearly 

 sessile, rather crowded : calyx green, nearly a line long, much exceeding the calycu- 

 ; Tate bracts, strongly nerved, the lobes much shorter than the small petals : ovary 

 obliquely truncate, often 1-ovuled: stigma small. — Bot. Beechey, 139, t. 30 ; Torr. 



6 Gray, Fl. i. 430. 



Var. obtusifolium, Watson. Leaves short, obtuse : branchlets usually puber- 

 ulent. — A. brevifolia, Nutt. 



Abundant on dry soils in the Coast Ranges and more rarely in the foot-hills of the Sierra 

 Nevada, from S. California to Lake Co. (Torrcy) and Sierra Co., Lemmon. The variety near San 

 Diego. It is usually 6 or 8 feet high, often covering extensive areas with a dense and almost 

 impenetrable chapparal or "chamisal," producing an effect upon the landscape similar to that 

 of the heaths of the Old World. 



