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REFERENCE TO RHODODENDRON CAUCASICUM, BY VARIOUS 
AUTHORITIES, COLLATED BY G. W. E. LODER and J. C. WILLIAMS. 
Rhododendron caucasicum, Pallas. Syn. Rh. caucaseum. 
Introduced in 1803. 
Plate in Pallas “ Flora Rossica,” 31 (published 1784). 
,, Bot. Mag., 1145. 
Mr. W. J. Bean, in “ Trees and Shrubs Hardy in the British Isles," Vol. 
11., p. 349, gives the following information ;— 
Rh. caucasicum, 2 feet, flowers yellowish-white or with a pale lilac tinge, 
produced during June, and the following varieties and hybrids are enumerated :— 
chrysanthum, Pallas. There is a plate of this in Pallas “ Flora Rossica,” 
No. 31. From Siberia and N.E. Asia, nearly aUied to Rh. caucasicum, yellow 
flowers, and differs in its smaller leaves, quite smooth on both surfaces. Very 
unsatisfactory in cultivation, and never seen in flower by Mr. Bean. 
CAUCASICUM PiCTUM. " Nearly allied to ” caucasicum. 
Cunningham’s White, raised by James Cunningham, of Comely Bank, about 
1830, between caucasicum and ponticum album. (Syn. caucasicum album.) 
Nobleanum (caucasicum X arboreuin). Bot. Reg. 1820. 
pulcherrimum (caucasicum x arboreum), Bot. Reg. 1820. 
ROSA mundi. ‘‘ Very near caucasicum in leaf and habit.” 
STRAMiNEUM. Pale yellow flowers. Bot. Mag., 3422. 
SULPHUREUM (caucasicum X arboreum album). Raised at Cunningham 
and Fraser’s Nursery, Comely Bank, Edinburgh. 
VENUSTUM. Raised by Mr. W. Smith, of Norbiton, near Kingston, between 
caucasicum and arboreum. 
Jacksoni. ‘‘ An identical plant,” said to come from caucasicum crossed 
with Nobleanum, raised by Mr. Jackson, also of Kingston. 
(N.B.—Professor Bayley Balfour writes that there are two Rliododendrons 
known as Jacksoni in gardens, and states that Rh. chrysanthum is 
quite a distinct species. See letter dated 8th November, 1916, attached.) 
Schneider, in Vol. II., p. 482 (published 1912), gives Flavidum, Regel, as a 
variety of caucasicum, and enumerates the foUowing hybrids :— 
CAUCASICUM X CATAWBIENSE. 
“ Cunningham’s White ” (no parentage given). 
CAUCASICUM X PONTICUM=“ CAUCASICUM HYBRIDUM.” 
CAUCASICUM X ARBOREUM=PULCHERRIMUM and NoBLE.4NUM. 
Rh. chrysanthum, Pallas, is given as a separate species not as a variety 
of caucasicum. 
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