97 — ROSA INVOLUTA, var. WILSONI Baker 
_ Rosa involuta , var. Wilsoni : a typo recedit foliolis simpliciter serratis, saepe 
basi cordatis, facie glabris, dorso leviter ptibescentibus ; sepalis simplicibus vel 
exterioribus parum compositis ; fructu ampullaeformi. 
R. involuta, var. Wilsoni Baker in Journ . Linn . Soc. vol. xi. p. 208 (1869). 
R. Wilsoni Borrer in Hooker, Brit. FI. p. 228 (1830) ; Eng. Bot. Suppl. vol. ii. 
t. 2723 (1834). — Syme in Eng. Bot. ed. 3, vol. iii. p. 206 (1864). 
R. tomentosa x pinipinellifolia , var. Wilsonii Keller in Ascherson & Graebner, 
Syn. Mitteleur. FI. vol. vi. p. 342 (1902). 
Stem erect, 3-4 feet high, bright red-brown in exposure ; prickles moderately 
dense, straight, slender, scattered, passing gradually into aciculi. Leaflets 7, 
middle-sized, oblong, subobtuse, broadly rounded or cordate at the base, simply 
toothed, glabrous above when mature, somewhat pubescent, not glandular beneath ; 
petioles glandular and pubescent ; stipules adnate, gland-ciliated, with small, ovate, 
free tips. Flowers 1-3 ; peduncles with glandular and eglandular setae. Calyx- 
tube broadly ovoid, naked or more rarely setose ; lobes lanceolate, f in. long, densely 
glandular on the back, simple, or the outer slightly compound. Petals bright pink, 
middle-sized. Styles free, densely villous, not protruded. Fruit urceolate, bright 
red, pulpy, erect, crowned by the erect persistent sepals. 
This is one of the rarest of our native plants, its classic locality 
being on the south bank of the Menai Straits, near Bangor. It was 
discovered about 1820 by W. Wilson, the well-known bryologist, 
author of Bryologia Britannica. A similar plant was found by Dr. 
David Moore at Umbra Rocks, Co. Derry, Ireland, but nothing quite 
like it has been collected on the continent. It is an erect bush, some 
two to three feet in height, with pink flowers, and has an appearance 
between that of Rosa spmosissima L. and Rosa tomentosa Sm. ; it is no 
doubt a hybrid between these two species. It is often called the Irish 
Sweet Briar ; it comes into leal very early in the season, and is nearly 
as fragrant as the true Sweet Briar. In cultivation it loses some of 
its characters and becomes stronger and more luxuriant in growth. 
The varieties making up the group Sabiniae are linked to each 
other by their extreme forms to such an extent that it is very difficult to 
distinguish between them. This is not surprising when it is recollected 
that the whole series is of hybrid origin, between Rosa spinosissima L. 
on the one hand and Rosa tomentosa Sm. and Rosa mollis Sm. on 
the other. 
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