Cfje l^fjobobenbron ^oteg. 
The archives of the Petrograd Herbarium will have to be searched to obtain a 
complete picture of the area which it is recorded as covering. The information I 
have gathered tells of its occurrence from the Altai on the west, eastwards along 
the snow ridges of Sajan, then around Lake Baikal and down the Amur, in fact, 
along the Siberian-Mongolian-Manchurian Divide. Thence into Kamtchatka 
and the Islands of the Behring Sea, and southwards into Yeso, and the high hills 
in Central Japan. The distribution is quite a natural one in the light of what 
we conjecture of the peopling by plants of this surface of the earth. The phar¬ 
maceutical virtues of chrysanthum has probably led, as Pallas says, to its 
distribution by man beyond the bounds to which nature would have allowed it 
to spread. There are several stations for it in Japan. I saw it in the Alpine 
Garden at Nikko, in the neighbourhood of which it grows, and have a good 
specimen from the Nikko Hills, sent to me by Mr. Mochiguki, the custodian of 
the Garden. But its best home in Japan is the Hiva and Etchm range further 
west than Nikko, the high hills of which I was only able to gaze on with longing 
eyes. I have not seen the * article by Wilson, of which you speak, and shall look 
out for it. 
I. BAYLEY BALFOUR. 
Professor Bayley Balfour to Mr. G. W. E. Loder. 
Royal Botanic Garden, Edinburgh, 
%th November, 1916. 
Dear Mr. Loder,— Thank you very much for letting me see the notes upon 
Rh. caucasicum, which I take it pretty well include all that is on record about 
CAUCASICUM. Rh. chrysanthum is quite a distinct species. You refer to the 
colour of the flower in Pallas’s figure, and the contrast with the description is 
striking, but I note that those white-pink Rhododendrons often take on, as they 
olden, this lilac colour. 
As regards my mention of the two Jacksoni’s, our old Jacksoni, which has 
been here as long as I can remember, is a plant which strikes me as being a 
secondary hybrid from Nobleanum. It is a more useful plant than Nobleanum. 
It comes into flower about a fortnight later, and therefore, more often misses the 
early spring frosts. It forms trailing branches and large trusses of flowers 
slightly paler than Nobleanum, and sometimes slightly fringed. It is the freest 
of flowerers, and never fails. Many years ago I wanted more of it, and bought 
in the market the Jacksoni of commerce, but it proved to be altogether a 
different plant—really not very different from caucasicum pictum. One of our 
expert Rhododendron growers here told me that this form is the modern 
Jacksoni. It is worthless compared to the old Jacksoni. 
Nobleanum was raised by Cunningham and Fraser here, at the same time as 
by the Nobles, in the south, and to this day, Cunningham and Fraser maintain that 
they had it first, and their parentage to me is yellow caucasicum crossed with red 
ARBOREUM. There is one feature in Nobleanum which your investigation might 
throw light upon, and which might also throw light upon your investigation. 
* The Garden Mag.\zine, for June, 1916, published New York. 
9 
