38 ERICACEAE 



Mackie; Soldier Ridge, se. Trinity Co., Jepson 14,718; South Fork Mountain, Chesnut 4" Drew; 

 Trinity Summit, Jepson 2047; Shackleford Creek, w. Siskiyou Co., Butler 101. Ore.: Ashland 

 Butte, Jepson. 



Eefs.— Arctostaphylos nevadensis Gray, Syn. Fl. 2:27 (1878), type loc. "Sierra Nevada, 

 8000 to 10,000 ft."; Jepson, Fl. W. Mid. Cal". ed. 2, 313 (1911), Man. 748 (1925). Uva-ursi 

 nevadensis Abrams, N. Am. Fl. 29:94 (1914). 



6. A. myrtifolia Parry. Ione Manzanita. Low diffuse shrub % to 1^^ feet 

 high, the stems decumbent or spreading ; branchlets of the season glandular-hirsute 

 with stiff spreading hairs, the older branchlets glabrous, mostly glaucous or gray ; 

 bark of branchlets shreddy ; leaf -blades narrowly ovate, sometimes elliptic or oval, 

 mostly obtuse at base, acute (or rarely obtuse) and mucronate at apex, 3 to 6 (or 9) 

 lines long, microscopically hireutulose or glabrous; corolla small (2 Imes long) ; 

 berry globose. 



Rocky or shaly slopes, 400 to 800 feet : Amador Co. foothills between Sutter 

 Creek and Jackson Creek. Jan. -Feb. 



Field note. — Arctostaphylos myrtifolia forms pure colonies. The low shrubs have a red- 

 brown color which is distinctive. On this account the traveler can recognize this species over a 

 considerable extent of country between lone and Buena Vista. The colonies are often circular 

 or band-like (% mile long and 80 yards vride) ; they are sharply defined and when band-like 

 sometimes march across the summit of a hill-top like a "fire lane." Those rocky hills where it 

 gro%vs also support high chaparral, Arctostaphylos viscida and scrub Quercus \visUzenii, with 

 an occasional tree of Pinus sabiniana. From a point on the Buena Vista road one may observe 

 about 1200 acres of pure colonies of Arctostaphylos myi-tifolia. 



The main stems of the bushes are much flattened vertically. They become % to 1% inches 

 broad and 2 to 5 lines thick. The degree of flattening varies, but the stems are often remarkably 

 thin, suggesting broad ribbons, though much contorted or tmsted. They are always dead on the 

 upper side, but bear a cord-like band of living tissue on the lower side. Jos. E. Adams (a student 

 of the author) has studied the tissues of such stems anatomically and it is his view that the peculiar 

 structure is pathogenic although he was unable to discover a specific organism (Madroiio 2:147- 

 152). He did, however, make the important observation that such flattening of the stem may 

 also occur in shrubs of Arctostaphylos viscida in the same local region and that occasional shrubs 

 of A. myrtifolia do not exhibit flattened stems. 



Locs. — lone, Jepson 15,206; Buena Vista, Jepson 9961. 



Eefs. — Aectostaphylos myrtifolia Parry, Pitt. 1:35 (1887), type loc. ridges e. of lone, 

 Farry; Jepson, Man. 748 (1925). Uva-ursi myrtifolia Abrams, N. Am. Fl. 29:100 (1914). A. 

 nummularia var. myrtifolia Jepson, Madrono 1:85 (1922). 



7. A. nissenana C. H. ]\Ierriam. Eldoeado Manzanita. Erect shrub, 3 to 6 

 feet high ; bark reddish-brown, roughly fissured into narrow longitudinal strips ; 

 branchlets and petioles liirsute or hirsutulose with spreading hairs ; leaves rather 

 densely clothing the somewhat virgate or fastigiate branchlets, the blades elliptic 

 to ovate, mostly obtuse, mucronulate, % to 1 inch long, light green and thinly pu- 

 berulent when young, glabrate and white-glaucous in age ; petioles i/4 to 1 line long ; 

 corolla at first pinkish, later white, 2^^ lines long ; ovary glabrous ; berrj' glabrous. 



Dry ridges, 1600 to 3500 feet : Sierra Nevada foothills in Eldorado Co. between 

 the North Fork IMokelumne River and North Fork American River. Mar. 



Field note. — Arctostaphylos nissenana has been an obscure species and stiU remains in great 

 degree so. It was published without any description of the flowers or fruit and without notes 

 upon the life-history behavior. Search for it by the author at the easily accessible type locality 

 has been unsuccessful. Since its publication in 1918 perhaps only a half-dozen shrubs have been 

 seen by this writer. It is, however, doubtless not so extremely rare as would appear. When asso- 

 ciated with Arctostaphylos viscida it is, on account of its habit, hue and foliage, very easily 

 passed by for that species. The rough bark of the main trunk and branches furnishes the most 

 ready means for identification in the field. The longitudinal strips of bark become somewhat 

 loose and often impart a shaggy appearance to the trunk or main stems. On the branchlets, one 

 to five years old, the bark is smooth or smooth by exfoliation. The branchlets are usually rather 

 strictly erect. The leaves are markedly erect and persist two to four years, thus clothing for 8 

 to 14 inches the terminal portion of the branches. Crown sprouting does not occur. This de- 

 scription of the shrub is based chiefly on field observations near Plaeerville, about 8 or 9 miles 

 from the type locality. Non-tj-pical shrubs occur in the chaparral which appear to be hybrids. 

 The suggestion obtrudes, however, that A. nissenana may itself be a hybrid between A. viscida 

 and A. nissenana var. arcana. 



