BUCKTHORN FAMILY 



469 



intergradation series to the shrubs representative of the formal type of Ceanothus integerrimus 

 which inhabit the Santa Cruz Mountains about Mount Ben Lomond. 



The original specimens of Ceanothus integerrimus were collected by David Douglas in Cali- 

 fornia in 1831 and are preserved at the Eoyal Botanic Gardens at Kew, England (Herb. Hook.). 

 They are in character so unlike the prevailing shrubs of the Sierra Nevada as to suggest at once 

 that the name of Ceanothus californicus given the Sierra Nevada shrubs by Kellogg must be 

 taken up as representing a species distinct from the shrubs described as Ceanothus integerrimus. 

 The first to insist with much cogency on this view was E. L. Greene (Lflts. 1:65). We ourselves 

 studied the type specimens of Ceanothus integerrimus H. & A. at Kew in 1905 and again in 1926 

 and 1930. There are two sheets, quite alike : one in the Herbarium Hookerianum and another in 

 the Herbarium Benthamianum. The pinnate-veined character of the leaves, their thinness and 

 oblong outline are remarkable features. In a few of 

 the larger leaves the basal pair of nerves is, some- 

 times, rather strong, which would account, in our 

 opinion, for the otherwise anomalous phrase, "foliis 

 3-costatis", of the original diagnosis. The prevailing 

 type of leaf in all material is, however, that described 

 above, markedly oblong in some degree, pinnately 

 veined and thin. 



In May, 1888, C. C. Parry collected specimens 

 near Ben Lomond in the Santa Cruz Mts. which match 

 in a truly remarkable manner the type specimens of 

 Douglas at Kew. We know that Douglas was at 

 Santa Cruz during his stay in California. Since this 

 particular form has not been collected elsewhere, it 

 seems probable that Ben Lomond may be the original 

 locality for the Douglas specimens. Discovery of the 

 Ben Lomond locality was made a little prior to Parry 

 by C. L. Anderson ; and there have been subsequent 

 collections. All this material is almost singularly uni- 

 form and is remarkable for the oblong or oblong- 

 elliptic leaves which are 5 to 13 lines long, rounded 

 at both ends, quite thin, and as if glabrous or only 

 minutely puberulent. As of greatest significance, the 

 leaves are delicately pinnate-veined. The capsules, 

 2 lines wide, are crestless or perhaps sometimes weakly 

 glandular-crested. Cf. fig. 231. 



Assuming C. L. Anderson to be the original dis- 

 coverer. Parry named the Ben Lomond shrub Ceano- 

 thus andersonii, although he had first distributed 

 specimens of it under the name Ceanothus palmeri 

 Trel., a shrub of the mountains of San Diego Co. 

 The leaves of Ceanothus palmeri in shape resemble 

 closely those of the Ben Lomond shrub and are pin- 

 nately veined. They are, however, slightly thicker, a 

 difference evidently to be correlated with the greater 



aridity of the Cuyamaca Mts. as compared with the Santa Cruz Mts. Ceanothus palmeri and 

 Ceanothus integerrimus of Ben Lomond have a certain similitude, but are here regarded as 

 definitely different imits. 



On the other hand the problem as between typical Ceanothus integerrimus and the Sierra 

 Nevada shrubs is not simple. If the dominant form of the Sierra Nevada may under a change 

 of conditions develop small thick oblong leaves obscurely pinnately veined as in the inner Coast 

 Eanges, may it not develop thin pinnately veined oblong leaves as an adaptation in the Santa 

 Cruz coastal forests? It is a question to be resolved by further field studies, or better by garden 

 cultures. As it is, we leave, for the present, the Sierra Nevada shrubs in possession of the name 

 Ceanothus integerrimus which they have borne so long. The problem is, however, an interesting 

 one — the most interesting in Ceanothus which is at once historical and ecological. It should be 

 added that in Gray's Synoptical Flora (1^:411) the original Ceanothus integerrimus is described 

 under the name Ceanothus andersonii Parry and is held as distinct from the Sierra Nevada shrubs. 

 Three stations near Ben Lomond village were found by J. T. Allen in 1935. One of these repre- 

 sents the original thin-leaved pinnate-veined type; another exhibits thicker leaves, pinnately 

 veined on the branchlets, strongly 3-nerved on the main branches. 



Deer Brush is usually semi-deciduous, but some leaves persist all winter. It may, in favor- 

 able habitats, as on north slopes, form a nurse cover for coniferous seedlings. In such cases it is 

 eventually shade-killed as the new forest establishes a more complete crown canopy. 



Locs. — Sierra Nevada : Bowens Sprs., Modoc Co., M. S. Baker 516 ; Upper Fall Eiver Valley, 

 ne. Shasta Co., Jepson; Cow Creek Mts., Shasta Co., M. S. BaTcer; Stirling, Butte Co., Jepson; 



Fig. 231. Ceanothus integerkimus 

 H. & A. DraAving of a specimen from 

 Ben Lomond, Santa Cruz Mountains, C. 

 C. Parry, May, 1888, which compares ex- 

 actly with the Douglas type in the her- 

 barium of the Eoyal Botanic Gardens at 

 Kew, England, a, flowering branch, X 

 1/4 ; i, leaf, X % ; c, capsule, X 3. 



