HEATH FAMILY 33 



feature. Habit or form ia frequently of marked value. As a rule it is the sum total of characters 

 in Arctostaphylos that qualifies a species, rather than one or two constant marks. 



The flower in Arctostaphylos is very uniform throughout the group, exhibiting only slight 

 differences in the various species. Similarly the inflorescence is very uniform in structure ; less 

 commonly is it distinctive, though often exhibiting somewhat intangible or minor differences. 

 The months from January to April cover the flowering periods of most species. The embryonic 

 panicles are, however, developed in the preceding May to July and remain dormant for six to 

 nine months. During the dry fall season the shrubs, therefore, bear, antecedent to the flowering 

 panicles, structures which are peculi.ar. When trailing in the Napa Kange in September, 1915, 

 the author first made record in his field book of the embryonic panicles of Arctostaphylos stanfor- 

 diana which are markedly different from those of the associated Arctostaphylos manzanita : those 

 of the former are very slender, elongated, erect, glabrous, and bear small buds ; those of the latter 

 are coarser, pendulous, puberulent and bear large buds. The embryonic panicles of Arctostaphy- 

 los elegans are different from either: they are coarse, minutely puberulent, consisting commonly 

 of several to many simple branches, all of which, closely parallel, curve a little in one direction, 

 that is outward or downward ; the bracts are short and broad but nearly conceal the buds. In the 

 case of Arctostaphylos viscida the panicle from August to November is extremely small, consist- 

 ing of 1 or 2 very short branches with acuminate bracts which almost completely hide the buds. 

 The embryonic panicles of Arctostaphylos canescens are stoutish, compact, curved, densely long- 

 bracteate and white-pubescent. In Arctostaphylos glandulosa the branches of the embryonic 

 panicles are few and curve a little ; the bracts are not so congested as in Arctostaphylos canescens 

 and tend to be suddenly contracted above the broad base which conceals the bud. 



In the case of Arctostaphylos viseida the embryonic panicle is extremely small, consisting of 

 one or two or few very short slender branches with acuminate bracts which almost completely hide 

 the buds. The closely related Arctostaphylos mariposa exhibits similar embryonic panicles, the 

 branches being a little stouter than in Arctostaphylos viscida and the bracts perhaps less acumi- 

 nate. The slight difference in the embryonic panicles of these two species reflects the weakness of 

 other differences or presumed differences which have been used to sustain Arctostaphylos mariposa 

 as a distinct species. The most common species in the Sierra Nevada belt above Arctostaphylos 

 viscida is Arctostaphylos patula. The panicle branches in this species are several, diverging a 

 little, with the bracts distinctly spreading at right angles to the rachis as contrasted with the 

 closely appressed bracts of both Arctostaphylos viscida and mariposa. 



The above notes on the embryonic panicles began with the representation in the Napa Eange, 

 thence to Mt. Konocti in Lake County, and has been only partially extended over the state. It 

 seems probable, nevertheless, that in all species the embryonic panicles will be found to exhibit 

 characteristics which will be of value in either a positive or negative manner. Here is a source of 

 character differential which could not have been predicted. Unquestionably there are other ele- 

 ments in the field of the life history of these species awaiting discovery. 



Contributions to our knowledge of Arctostaphyli in western America have been made by a 

 number of authors. Such contributions, diagnoses of new species and taxonomie accounts of the 

 genus, have extended the field of knowledge, but at the same time also multiplied greatly the prob- 

 lems by reason of the very nature of the group and its development. It is, therefore, no reflection 

 upon the distinguished botanists who have had to do with the publication of new species in this 

 genus to say that an extended monograph of Arctostaphylos is now a desideratum. No revision will 

 answer, however, which restricts itself to the usages of taxonomie formalism, to the morphological 

 features usually depended upon in systematic botany, such as shape of leaf, color of flower and 

 details of pubescence and glandulosity. The attack must be on the broadest possible basis and 

 broad consideration given in the field to certain objectives, which may in part be listed, in relation 

 to each species, as follows: (a) study of habitat; (b) study of form; (c) statistical notes on 

 range of variation in vegetative organs; (d) evaluation of glands and glandular development and 

 degree of variation; (e) kinds and character of trichomes, their variation and their degree of 

 persistence; (f) reproductive organs; (g) extent of interbreeding under natural conditions; (h) 

 seed production, character of seedlings and of reproduction in the juvenile stage; (i) develop- 

 ment of root-crowns and burls; (j) reaction to chaparral fires; (k) seed hibernation and seed 

 longevity under natural conditions ; (1) associated species; (m) centers of distribution ; (n) de- 

 gree of constancy throughout range ; (o) study of minor forms; (p) climatic factors ; (q) relation 

 of a given type or form to minor climatic areas; (r) correlation of distribution with chemical 

 characters of soils or with a definite degree of soil acidity; (s) relation of the species or minor 

 forms to fault blocks large and small and their geological history; (t) the organism as a whole 

 and the discovery of as yet unknown constants or factors which in all probability exist. It ia 

 peculiarly true in Arctostaphylos that no tests can be applied in this genus for the species as a 

 whole, but that each species must be worked out on its own basis as to the significant criteria for 

 that species. 



The problem of Arctostaphylos in the Coast Eanges is very unlike that in the Sierra Nevada. 

 In the Sierra Nevada the species are fewer and are, on the whole, relatively constant throughout 

 the length of that mountain chain. There are only two narrow endemics in the Sierra Nevada: 

 one, Arctostaphylos nissenana in the Eldorado County foothills, the other, A. myrtifolia in the 

 Amador County foothills. In the Coast Ranges, on the contrary, there are not only a larger num- 



