ROSACEA. SILVA OF NORTH AMERICA. 17 
PYRUS RIVULARIS. 
Oregon Crab Apple. 
LEAVES ovate-lanceolate, serrulate, often 3-lobed, pubescent on the lower surface. 
Pyrus rivularis, Douglas; Hooker, Fl. Bor.-Am. i. 203, t. Pyrus fusca, Rafinesque, Med. FV. ii. 254. 
68. — Don, Gen. Syst. ii. 647. — Torrey & Gray, Fl. N. Pyrus subcordata, Ledebour, FV. Ross. ii. 95. 
Am. i. 471. — Walpers, Rep. ii. 53.— Dietrich, Syn. iii. Malus rivularis, Roemer, Fam. Nat. Syn. iii. 215. — De- 
154. — Ledebour, FV. Ross. ii. 99. — Nuttall, Sylva, ii. 22, caisne, Nouv. Arch. Mus. x. 155. 
t. 49. — Torrey, Bot. Wilkes Huplor. Exped. 292. — Koch, Malus diversifolia, Roemer, Fam. Nat. Syn. iti. 215. — De- 
Dendr. i. 212. — Wenzig, Linnea, xxxviii. 38. — Brewer caisne, Nouv. Arch. Mus. x. 155. 
& Watson, Bot. Cal. i. 188.— Sargent, Forest Trees N. Malus subcordata, Roemer, Fam. Nat. Syn. iii. 192. 
Am. 10th Census U. S. ix. 73. Pyrus rivularis, 8. levipes, Nuttall, Sylua, ii. 24. 
Pyrus diversifolia, Bongard, Mém. Acad. Sci. St. Péters- 
bourg, ser. 6, ii. 133. 
A tree, thirty to forty feet in height, with a trunk twelve to eighteen inches in diameter; or often 
a shrub sending up from the ground many slender stems. The bark of the trunk is a quarter of an 
inch thick, the surface broken into large rather thin loose light red-brown plate-like scales. The winter- 
buds are obtuse, one sixteenth of an inch long, and covered by chestnut-brown scales rounded on the 
back and ciliate on the margins; the accrescent scales of the mner rows being lanceolate-acute when 
fully grown, usually bright red, and nearly half an inch long. The branches are at first coated with 
long pale hairs which are sometimes deciduous, and sometimes cover them more or less completely 
until the autumn ; in their first winter they become bright red and lustrous, and later are dark brown 
and often marked by minute remote pale lenticels. The leaves are ovate-lanceolate, acute or acuminate 
at the apex, wedge-shaped or rounded at the base, sharply serrate with appressed glandular teeth, and 
occasionally, especially on vigorous shoots, obscurely three-lobed, with prominent midribs and primary 
veins grooved on the upper side, and conspicuously reticulate veinlets ; when they unfold they are pubes- 
cent on the lower, and puberulous on the upper surface, and at maturity are thick and firm, dark green 
and glabrous above, and pale and slightly pubescent below, an inch to three inches long, and half an 
inch to an inch and a half broad, and are borne on stout rigid pubescent petioles an inch to an inch 
and a half in length. The stipules are narrowly lanceolate, acute, from one half to three quarters of 
an inch long, and caducous. In the autumn the leaves assume beautiful shades of orange and scarlet. 
The flowers, which are produced in short racemose many-flowered cymes leafy at the base, are borne on 
slender pubescent pedicels biglandular near the middle, and are half an inch across when expanded; the 
calyx-tube is narrowly obconic and glabrous or puberulous, with acute lobes, minutely apiculate, coated 
with dense pale tomentum on the inner surface, and deciduous from the mature fruit; the petals are 
orbicular to obovate, with erose or undulate margins; they are contracted below into short claws, and 
are as long as the two to four glabrous styles. The fruit, which ripens in September and October, is 
obovate-oblong, and from one half to three quarters of an inch in length, with thin dry flesh and 
large seeds; on some trees it is yellow-green when fully ripe, and on others it is light yellow with a red 
flush on one side, or sometimes is almost entirely red. 
Pyrus rivularis is distributed from the Aleutian Islands southward along the coast and islands of 
Alaska and British Columbia’ and through western Washington and Oregon to Sonoma and Plumas 
1 Richardson, Arctic Searching Exped. ii. 294, — Rothrock, Smithsonian Rep. 1867, 435 (Fl. Alaska). —G. M. Dawson, Canadian Nat. 
n. ser. ix. 330. 
