■1 I'liin rsil If of ('(ilifuniid I'lihJicaiions in Botany [Vol. 7 



pereniii.-il hci'lis .-n-c round (•(i\ci'iii<j- the <_m-()uiii1 iiii<lcr llicse trees and 

 shrubs. Trilliitni sessile var. (jiyanh iiin ^m-ows in <fi'c;i1 ahimdanee 

 ill lliis rog:ion, l)\i1 (lisapjx'ars some eight miles east of S;iii Francisco 

 liny, reappearing in Ihe middle Sici-i-;! Nevada. In addition to the 

 prevailing format ioii.s noted abovr. I'cdwood forest occurs in unusually 

 moist canons of CentT-nl Cnlifoi-nia, such as those on Mount Tamalpais 

 and in San Ticandro ('anon. Trillinm ovahdii regularly appears in 

 these localitii's. soiucl iincs in great abundance, while T. sessile var. 

 gignnteiim occurs only on the edges of these groves. 



Three species of Trillium are with certainty to be distinguished 

 as occurring in California. The total range of all the west coast species 

 extends at least from Washington south to San Luis Obispo County, 

 California. The pedunculate species of California are two — T. ovatum 

 Pursh.. and T. nivale Watson. The latter species is not too well 

 known but is reported as characterized by a short, slender habit, 

 petioled leaves, long pedunculate flowers and in general to be "allied 

 to T. nivale Riddell, which it much resembles in habit." This species 

 we have not collected and is not to be dealt with in what follows. 

 Trillium ovaUim is sometimes referred to as the west coast form of 

 T. grandiftorum (]\Iichx.) Salisb., from which, however, it is in fact 

 distinctly set apart. In height ovafum ranges from 6 to 30 cm. from 

 the surface of the ground, the height of the great majority of the 

 plants falling between 20 and 26 cm. Where the natural cover has 

 disappeared, as in burned-over areas, the west coast species of Trillium 

 are greatly reduced in height but vegetative and floral organs are 

 not diminished as to size. In general, height of plants seems scarcely 

 worthy of notice in this genus where the character can be varied at 

 will. This i)oint is emphasized in the reaction shown by the ])lants 

 figured in plate 1, figure 2. All the four plants were kept under a 

 shed which was open at one side. The two middle plants were grown 

 near the open side and were fully and on all sides almost equally 

 illuminated, while the two plants at either end were grown toward 

 the back of the shed in greater shade and illuminated from one side 

 only. During the year preceding and in the year following when 

 all were growing under the same conditions their height was closely 

 corresponding. The above is mentioned here not because the 

 observed reaction is other than the one to be anticipated, but because 

 the difference in height and habit of the two groups is out of all 

 proportion to the relatively slight difference in growing conditions, 

 in other words, plants of Trillium species appear to be so markedly 



