CHAP. XLII. ROSA‘CER, PU RSHIA. TOY 
Soil, Situation, §c. A deep, free, dry soil, and a sheltered situation, are 
essential to this species; which, north of London, as already observed, will 
be safest placed against a wall, or, probably, grafted on the Portugal laurel. 
In the London nurseries, it is propagated from seeds; and plants, of which 
there are now (1836) abundance in the Fulham, Epsom, and Milford Nur- 
series, are Is. 6d. each. 
App. i. Other Species of Cérasus. 
In De Candolle’s Prodromus, and in Don’s Miller, two West Indian, and four South American, 
species are described; but only two of these (C. sphzrocarpa Lois., P. spherocarpa Swartz, Don’s 
Miil., ii. p. 516. ; and C. occidentalis Lozs., and Don’s Miil., ii. p. 516., P. occidentalis Swartz) have 
been introduced into Britain. They are both considered hot-house plants, but might, probably, be 
acclimatised. Rafinesque, under the article Prinus, in his Medical Flora, vol. ii. p. 453., says that he 
has prepared a monograph of 40 wild American species of Prinus ; under which genus, with Lin. 
nzus, he includes both plums and cherries; only 25 of which, he says, are described by authors : 
but we are not aware that any work of this description has been published. 
Sect. II. Spire ‘z. 
Genus VI. 
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i x 
PU’RSHIA Dec. Tue Pursnia. Lin. Syst. Icosindria Monogynia. 
Identification, Dec. in Trans, of Lin. Soc., 12. p. 157. ; Prod., 2. p. 541. ; Lindl. in Bot, Reg., t. 1446. ; 
Don’s Mill., 2. p. 517. 
Synonyme. Tigdrea Ph, Fl. Amer. Sept., 1. p. 33., not of Aublet. 
Derivation. Frederick Pursh first characterised the only known species in his Flora Americe Sep- 
tentrionalis, and named it Tigdrea tridentata.. The generic name, however, having been preoccu- 
pied by Aublet, De Candolle has named the present genus after Pursh himself, 
% 1. P. rRIpENTA‘TA Dec. The 3-toothed-/eaved Purshia. 
Identification. Dec. in Lin. Trans., 12. p. 157. ; Prod., 2. p. 541. 
Synonyme. Tigarea tridentata Ph. Fl. Amer. Sept., 1. p. 33. t. 15., not of Aublet. 
Engravings. Ph. Fl. Am. Sept., t. 15.; Bot. Reg., t. 1446. ; and our figs. 424, 425. 
Description, §c. A spreading subdecumbent shrub, scarcely exceeding 2 ft. 
in height, with numerous branches, small whitish leaves, and rather many 
424 small yellow flowers, which begin to 
Ay Ss expand about the middle of May, 
Me vf and thence continue, successively, 
“¥y into June. The leaves are grouped, 
wedge-shaped, and ending in 2—3 
teeth that are large for the size of 
the leaf, villose above, but covered 
beneath with a white tomentum. 
Buds scaly. Stipules none, or mi- 
nute. (Dec. Prod., ii. p. 541., and 
amplified from observation.) A native of North America, 
in pastures by the river Columbia. It was almost the only shrub to be seen 
through an immense tract of barren sandy soil, from the head source of 
the Missouri, to the Falls on the Columbia, and from 38° to 48° nN, lat. 
(Douglas, in Hook. Bor. Amer.) It was introduced in 1826. There are 
plants of this species, in the garden of the London Horticultural Society, 
about 2 ft. or 3 ft. high, which flower freely every year. They require a dry 
light soil; and cuttings of the young wood will root in sand under a hand- 
Baas: Plants, in the London nurseries, not being much asked for, are 2s. 6d. 
each. 

ve 

425 
36 2 
