ROSE FAMILY 225 



Ovary and drupe glabrous ; flowers in clusters ; corolla white ; style deciduous. 



Drupe subglobose or ovoid, 3 to 8 lines long ; leaves folded together lengthwise in bud. 

 Leaves deciduous ; drupe small, its flesh bitter or astringent. 



Flowers in corymbs; drupe bright red (Subgenus Cerasus) 1. P. emarginaia. 



Flowers in racemes; drupe dark red (Subgenus Padus) 2. P. virginiana. 



Leaves evergreen, usually spiny; drupe large, its flesh sweetish (Subgenus Latjro- 



CERASUS) 3. P. ilicifolia. 



Drupe oblong, purplish, % to 1 inch long ; leaves rolled up from one edge to the other in bud ; 



flowers in umbels (Subgenus Euprunus) 4. P. suhcordata. 



Ovary and drupe velvety-tomentose or pubescent ; flowers mostly solitary, sometimes in 2s or 3s ; 

 style more or less persistent ; all desert species. 

 Flowers pedicelled, 5 to 8 lines broad; leaves glabrous, convolute in bud (Subgenus 

 Armeniaca). 



Leaves broad or roundish; corolla white 5. P. fremontii. 



Leaves narrow; corolla light rose 6. P. andersonii. 



Flowers sessile, 2 to 3 lines broad; corolla white; leaves puberulent, con duplicate in bud 

 (Subgenus Emplectocladus) 7. P. faseiculata. 



1. P, emarginata Walp. Bitter Cherry. Deciduous shrub 3 to 8 feet high, 

 very rarely arboreous and 20 feet high; bark smooth, dull red; leaf -blades ovate or 

 more commonly oblong-obovate, mostly obtuse, finely serrulate or crenulate, % to 

 2 inches long, on petioles 1 to 3 lines long; blade usually with 1 or 2 glands just 

 above junction with petiole; flowers 4 to 6 lines wide. 3 to 10 in short corymbs; 

 drupes bright red, ovate to globose, 4 to 5 lines long, the pulp intensely bitter. 



Rocky mountain ridges, rich moist slopes or hollows and along streams : South- 

 ern California mountains, 5000 to 9000 feet; Coast Ranges, 500 to 5000 feet; 

 Sierra Nevada, 4000 to 8000 feet. North to Idaho and British Columbia. Apr.- 

 May near the coast, June-July in the high mountains. 



Note on the type. — In the type specimen of Prunus emarginata, the leaves are obtuse or 

 sometimes obscurely retuse but not "emarginate" ; they are essentially glabrous, as are also the 

 pedicels and calyces; the petioles have 2 or 3 glands near the summit; C. F. Balcer 691 (Crystal 

 Springs Lake, San Mateo Co.) matches the tjT)e very closely. The type of Prunus (Cerasus) 

 mollis (Dougl.) does not differ notably from the type of P. emarginata save that the peduncles, 

 pedicels and calyces are markedly pubescent, the leaves beneath somewhat pubescent (Eoyal 

 Botanic Gardens, Kew, in June, 1930). 



Note on variation. — The two species named by Douglas, Prunus (Cerasus) emarginata and 

 Prunus (Cerasus) mollis are both from the Columbia River region, the first a glabrous shrub, the 

 second a pubescent small tree. The plants of the group cannot, however, be separated upon this 

 basis. The tree form may be glabrous, and the low shrubs (Eureka, Tracy 4780) may be as 

 pubescent as trees from the same general locality. The small trees of Strawberry Canon, Berke- 

 ley (Jepson 9633), although practically glabrous, may reach a height of 26 feet. 



Ten new segregates of this group named by E. L. Greene (Proc. Biol. Soc. Wash. 18:56-60) 

 are based upon such characters as the height of the plants, amount of pubescence on various 

 structures, shape and size of leaves and drupes, size and position of glands, and especially upon 

 the shape and surface irregularities of the stones, all weak and variable characters in this group. 

 The petiolar glands often vary as to one individual and the slight changes in pubescence are 

 indefinable. The stones, likewise, vary so much in individual plants, with regard to marginal 

 ridges and rugosities, that the character can have little significance as a criterion of segregation. 



The rocky ridges and exposed mountain sides on the west slope of the Sierra Nevada bear 

 for hundreds of miles, from one end of the range to the other, especially between 5000 and 8000 

 feet, extensive colonies or brush fields of this species. This form is shrubby, 4 to 8 feet high, 

 tending to be glabrous, with small and commonly narrow leaf -blades (typically % to 1^/^ inches 

 long, 3 to 6 lines wide). In protected situations or in moist swales on the same slopes the in- 

 dividuals often become more or less arborescent, 10 to 30 feet high, with leaves typically 1% 

 to 2 inches long and 6 to 11 lines wide. This latter form may be more or less pubescent, and a 

 given mountain side will show many intermediates to the glabrous states. Or again, broad- 

 leaved shrubs may grow on the rocky talus (Bubbs Creek, South Fork Kings Eiver, Jepson 798). 

 In general it may be said, however, that the plants of the same colony vary within much smaller 

 limits than does the species as a whole. The specimens cited below represent a series of con- 

 tinuous though slight variations. 



Locs.— S. Cal. : South Fork Eock Creek, San Gabriel Mts., Peirson 492 ; Coldwater Canon, 

 San Gabriel Mts., Peirson 2152; Bear Valley, San Bernardino Mts. (Zoe 4:342) ; Eaywood Flats, 

 San Bernardino Mts., Oilman; betw. Tahquitz and Bound Valley, Mt. San Jacmto, Munz 6032. 

 Coast Eanges: Santa Lucia Mts., PlasTcett; Los Gatos (foothills w.), Eeller 7301; Crystal Sprs. 



