the Rocky Mountains where, however, it extends over 
many degrees of latitude, reaching from Alaska through 
British Columbia, Oregon and Washington to California. 
It belongs to the same group of crabs as M. Toringo, 
Sieb. and M. Sargentii, Rehd., figured at t. 8757 of this 
work, all characterised by the calyx falling away from 
the apex of the fruit. From both the other species 
M. rivularis is well distinguished by its ellipsoid fruits 
and by the shorter lobes of the calyx as compared with 
the calyx-tube. The fruit has a rather pleasant acid 
flavour and is variable in size and colour. On our 
plant, which was obtained for Kew from a continental 
nursery in 1905, they appear to be larger and more 
cylindrical than is usual. According to Sargent this 
crab in a wild state affects moist situations where the 
soil is deep and rich, often forming in such places large 
impenetrable thickets. Archibald Menzies, the surgeon 
and botanist attached to Vancouver’s expedition of 
"survey, appears to have been the first European scientific 
observer to find it, which he did about 1793. David 
Douglas collected it some thirty years later, and it is 
said by Loudon to have been introduced in 1836. It 
has never been much cultivated in English gardens, 
although it is very hardy and grows vigorously, and is 
quite attractive when laden with its distinct and hand- 
some fruits. 
Description.—Tree, 15-30, sometimes 40 ft. high, the trunk 1-13 ft. in 
diameter; young shoots clothed with grey hairs at first, becoming glabrous; 
purplish-brown the second season. Leaves deciduous, ovate to ovate-lanceolate, 
acute or acuminate, usually rounded or occasionally cuneate at the base, 
sometimes obscurely lobed above the middle, finely and sharply serrate ; 
13-33 in. long, 3-13 in. wide; dark dull green, and at first puberulous above, 
finally glabrous ; paler and pubescent beneath ; petiole }-14 in. long, pubescent. 
Flowers 3-1 in. wide, terminal or produced in the axils of the terminal leaves, 
8-12 forming a corymb 2-3 in. wide, expanding in May. Calyx-tube obconic, 
pubescent; lobes 5, lanceolate, ;3: in. long, slightly pubescent or glabrous 
outside, thickly covered with pale grey wool within. Petals 5, orbicular with 
a short claw and a few jagged teeth near the base, % in. long, creamy white. 
Stamens 16-20; filaments glabrous, flattened. Styles 2-5 (usually 3) joined 
near the base, glabrous. Wruit ovoid-oblong, pendulous, }—3 in. long, 3 in. 
wide, glabrous, ripe in October and then yellow tinged with pink on the sunny 
side, greenish in the shade, the calyx falling away and leaving a sinall pit at 
the apex; peduncles slender, 1-1} in, long, glabrescent. Seeds +; in. long, 
pointed, compressed, pale brown, usually 3 in each fruit. 
Tax. 8798.—Fig. 1, unexpanded flower; 2, section of flower with petals 
removed ; 3 and 4, stamens; 5, section of fruit ; 6, seed :—all enlarged. 
