HEATH FAMILY 29 



Locs. — Upper Mission Caiion, Santa Barbara, Tucker 105; Topanga Canon, Santa Monica 

 Mts. (Bull. N. Y. Bot. Gard. 6:431), specimens not seen but perhaps the species and not the 

 variety; Eancho Santa Fe, B. D. Stark 857; San Diego, K. W. Sjimner. 



Var. planlfolla Jepson var. n. Shrub 6 to 20 feet high; leaf -blades elliptic to ovate, plane, 

 1 to 3 inches long; racemes 2 to 5 inches long; pedicels 2 to 6 lines long; calpc-lobes lanceolate 

 to subulate. — (Frutes 6-20 ped. altus; foliorum lamina elliptica vel ovata, plana, 1-3 unc. longa; 

 racemi 2-5 unc. longi.) — Santa Eosa, Santa Cruz and Santa Catalina islands. 



Locs. — Santa Eosa Isl. (Zoe 1:141) ; Ladys Harbor, Santa Cruz Isl., Mabel Peirson; Swain 

 Canon, Santa Catalina Isl., Jepson 3064 (type). 



Eefs. — CoMAEOSTAPHYUS WVERSIFOLIA Greene, Bull. Cal. Acad. 2:406 (1887) ; Jepson, Man. 

 744 (1925). Arctostaphylos arguta Zucc. var. diversifoUa Parry, Proc. Davenp. Acad. Sci. 4:35 

 (1883), type loc. Jamul Valley, San Diego, 0. N. Sanford. A. di/versifolia Parry; Gray, Syn. Fl. 

 ed. 2, 2:397 (1886). Var. PLANirouA Jepson. 



11. ARCTOSTAPHYLOS Adans. Manzanita 



Evergreen shrubs with very crooked branches, the bark dark red or chocolate- 

 color, smooth and polished. Leaves entire (rarely serrate), more or less vertical 

 by twisting of the petiole. Flowers white or pink, in a terminal usually subglobose 

 nodding cluster or panicle composed of few to several short racemes. Flower parts 

 usually in 5s. Bracts commonly scaly, sometimes foliaceous. Calyx of nearly dis- 

 tinct sepals. Corolla urushaped. Stamens twice as many as the corolla-lobes; 

 anthers with a pair of reflexed awns on the back; filaments more or less hairy, di- 

 lated toward the base. Ovary seated on a hypogynous disk, 4 to 10-eelled, with one 

 ovule in each cell, maturing into a dry brown beny-like fruit with an outer pulp 

 covering several stony 1-seeded nutlets. Surface of the berry smooth, the pulp at 

 first fleshy, at matm-ity usually mealy or powdeiy. Nutlets distinct, or irregularly 

 united in 2s or 3s, or sometimes consolidated into a single stone.- — The wood is hard 

 but brash, warping and cracking excessively in seasoning. The bark of the branches 

 during the summer exfoliates conspicuously in most species, and to some degree in 

 all species. The trunk or main stems in Arctostaphylos tomentosa and A. nissenana 

 have a rough shreddy bark and never become smooth. The panicles are sometimes 

 reduced to simple racemes, regularly so in some of the smaller species. The fragile 

 pericarp of the berries in Arctostaphylos nummularia and in A. myrtifolia is de- 

 ciduous and the fruit separates into 2 to 5 nutlets (sect. Micrococcus Parry; genus 

 Schizococcus Eastw.) . — Species about 35, Pacific Coast of Noi-th America, 1 species 

 extending east across the continent to New Jersey, north to arctic America, thence 

 circumpolar. (Greek arktos, a bear, and staphule, a bunch of grapes; bears feed 

 on the berries.) 



Biol. note. — A well-known indicator of the Transition Zone in the Sierra Nevada is Arctos- 

 taphylos patula, a spreading green-leaved shrub commonly 3 to 5 feet high. Its main stem or 

 stems arise from a globose woody root-crown lying at and a little below the surface of the ground. 

 The root-cro^vn is, in this species, a significant structure. It possesses the capacity to develop 

 regeneration shoots after the above-ground portion of the shrub is killed by fire or removed by 

 the axe. Such regeneration in Arctostaphylos is here spoken of as root-crown sprouting, a par- 

 ticular type of reproduction in the genus which occurs after fire; although this shrub also repro- 

 duces by layering of the lower spreading branches or by seed. Species characterized by root- 

 crown sprouting are here spoken of as root-crown shruis. 



By way of contrast we turn now to the foothills. The chaparral belt of the Sierra Nevada, 

 lying below the Transition Zone, is often dominated by Arctostaphylos viscida, or in the counties 

 from Calaveras to Fresno, by Arctostaphylos mariposa. Both are spreading shrubs, white-leaved, 

 3 to 6 or 12 feet high. Under chaparral fire both these species are completely killed; the root- 

 cro^vn is not developed into an enlarged structure and has no capacity to send up shoots after fire 

 or after mutilation. Seedlings are, however, produced in abundance, sometimes in astonishing 

 profusion, and promptly repossess burned territory. Shrubs which regenerate in this manner are 

 here called fire-type shrubs. 



The term fire-type shrubs is here used in a restricted sense as applying to those species, the 

 individuals of which are annihilated or completely destroyed by fire, have no means of regenera- 

 tion save by seed, but have developed several biological reactions in their life history to the cir- 

 cumstances of exclusive reproduction by seed. While root-croivn shrubs also display reaction to 

 fire, their relation to fire is not biologically specialized to so great a degree, since the individuals 



