HEATH FAMHiY 



37 



decumbent, forming a low rough mat. The bases of decumbent stems may strike adventitious 

 roots, but there is no capacity, as thus far observed, to develop new shoots from the root-cro^\Ti 

 after fire. As a result of fire over an area, the establishment of seedlings is stimulated. Young 

 plants eome into flower in their fourth or fifth year; Carl Purdy says they may flower in their 

 second year. This precocity is partial evidence of the fire-type character of the species. The 

 leaves are uniformly small. The bristles are persistent on the branchlets more than one year. 



This species also inhabits Mt. Tamalpais. Here the shrubs commonly have a single distinct 

 trunk a few inches to 2 or 3 feet high, thus differing slightly from the prevailing Mendocino coastal 

 plain type. Reaction to fire of the Tamalpais form was first de- 

 scribed by the author in 1916 (Madrono 1:7) under the name A. 

 sensitiva Jepson. The Tamalpais form is an erect shrub and is 

 usually gregarious. There is no swelling of the trunk at the ground 

 level. The root system is shallow, spreading horizontally just be- 

 neath the surface of the ground like an inverted umbrella. One can 

 readily overthrow a shrub 5 feet high ^\'ith a small foot-long botanical 

 pick. The shrubs are killed completely by chaparral fires and do not 

 sprout from the root-crown, but the "burn" promptly produces seed- 

 lings as the forerunner of a new stand. It is a genuine fire-type 

 shrub by reason of: (a) its shallow rooting; (b) outright destruc- 

 tion by fire; (c) exclusive reproduction by seed; (d) immediate re- 

 possessing of an area by seedlings; (e) the early age (5 to 8 years) 

 at which seedlings produce fruit, a period which is ordinarily shorter 

 than the fire interval. Anthesis covers several months ; sporadically 

 one may find shrubs in flower every month in the year. 



Locs. — Mendocino coast: Fort Bragg, Mathews; Mendocino 

 City, Jepson 2166a ; Albion, Davy 4- Blasdale 6068. Mt. Tamalpais : 

 Eldridge grade, Jepson 14,697 ; Muir Ridge, w. of Mill Valley, Jep- 

 son 14,730 ; zig-zag above Blithedale, Jepson 9502. Santa Cruz Mts. : 

 Butano forest, e. of Pescadero, San Mateo Co., Bracelin; betw. Bu- 

 tane and Little Butano creeks, Santa Cruz Mts., Dudley; Ben Lo- 

 mond, Elmer 4899 ; Bonnie Doon, Wiggins 5093. 



Refs. — Arctostaphylos ndmmulakia Gray, Proc. Am. Acad. 

 7:366 (1868), type loc. "plains near Mendocino City," Bolander 

 4749; Jepson, Fl. W. Mid. Cal. 370 (1901), ed. 2, 313 (1911), Man. 

 748 (1925), the last as to Mendocino plain shrubs. Vva-ursi num- 

 mtt?onaAbrams,N. Am. Fl. 29:100 (1914). ^. sensittiKi Jepson, Madrono 1:85, 94 (1922), type 

 loc. Pipe Line trail, Mt. Tamalpais, Jepson 5724; Man. 748, fig. 730 (1925). 



Fig. 296. Arctostaphy- 

 los NUMMULAKIAGray. Fl. 



branchlet, X %. 



5. A. nevadensis Gray. Pine-mat Manzanita. Gregarious undershrubs 

 roughly carpeting the forest floor, the main stems creeping or trailing, rooting, the 

 erect branches 3 to 6 or 9 inches high ; branchlets, petioles and racliises darkish or 

 brownish, minutely puberuleut ; leaf-blades obovate or oblong-oblanceolate, obtuse 

 and mucronate, or abruptly acute, glabrous or minutely puberulent, reticulate with 

 dark veins, 7 to 12 lines long ; panicle reduced to a raceme, small and compact (about 

 1/2 inch long) ; pedicels glabrous, 1 to 2 lines long; corolla pinkish, 2 lines long; 

 ovary glabrous ; berry subglobo.se, dark carmine, smooth, glabrous, 2 to 3 lines in 

 diameter ; nutlets distinct or partly united, narrow, ridged. 



Open pine woods : Sierra Nevada, 6000 to 9000 (or 12,000) feet, from Tulare Co. 

 to Modoc Co. and eastern Siskiyou Co.; North Coast Ranges (inner ranges mostly, 

 rarely in the middle range), 4700 to 7000 feet, from Mendocino Co. to western Sis- 

 kiyou Co. North to southern Oregon. June-July. 



Field note. — Arctostaphylos nevadensis is a characteristic feature of open pine woods at high 

 elevations in the Sierra Nevada, forming rough mats 3 to 10 feet broad and 6 to 16 inches high. 

 It is rare or at least seldom reported in the southern Sierra Nevada south of Mariposa County ; 

 it is common northward. On the ridges about the base of Lassen Peak proper, for example, it 

 forms extensive low brush fields in the scattered stand of Pinus contorta var. murrayana, Pinus 

 monticola and Tsuga mertensiana, and on some ridges is almost the only woody species aside 

 from the arboreous growth. Taxonomically it is very near Arctostaphylos hookeri Don. 



Locs. — Sierra Nevada: Mt. Moses, Tulare Co., Purpus 1369; White Chief Caiion, Mineral 

 King, Sawtooth Range, Sanford Eolley ; near Daulton Mdw., Kaiser Peak, Fresno Co., Jepson; 

 Glacier Pt., Tosemite, Jepson 5678 ; McClure Fork Merced River, Jepson 3223 ; Stanislaus Mdw., 

 Alpine Co., Jepson; Angora Lake, Eldorado Co., Ottley 867 ; Mt. Tallac, Jepson 8136 ; Big Silver 

 Creek, Eldorado Co., Kennedy 228; Summit sta., Nevada Co., Jepson 20,924; Mineral, Tehama 

 Co., J. Grinnell; Manzanita Creek, Lassen Peak, Jepson 15,316; Warner Mts., e. Modoc Co., B. C. 

 Goldsmith 31; Horse Camp, Mt. Shasta, Jepson 14,717. North Coast Ranges: Mt. Hull, W. W. 



