HUTCHINSON—THE MADDENI SERIES OF RHODODENDRON. 49 
leaves and twigs and consequently respiration is not interfered 
with, and along with this as a factor in the case is the harder 
growth of the plant which the situation evokes. This is not to 
be taken as an infallible prescription for horticultural practice, 
but our experience confirms me in believing that within the 
limits of the constitution of the plant rigorous environment, 
rather than genial, will give better results in the case of many of 
those plants which in our oscillating climatic conditions show 
themselves not quite hardy. 
“ Rh. Valentinianum like Rh. ciliatum is one of many species 
of Rhododendron which were placed by Maximowicz* in his 
Section Eurhododendron, but which have such fundamental 
characters of difference from other species of his Section that 
they cannot be associated together in one section. The bulk of 
the species known to Maximowicz and included in his Eurhodo- 
dendron possess a foliage-bud of remarkable construction which 
may be called a chamber-bud. By this designation | mean 
that the scale-leaves of the bud form a definite chamber at the 
bottom of which the primordia of the foliage-leaves arise each 
developing with a revolute ptyxis quite free from its neigh- 
bour. The young leaves stand erect in a group free within 
the chamber and only fill it up when the bud is on the way to 
maturity before expansion. There isa sharp distinction between 
the last scale-leaf and the first foliage-leaf. This type of bud 
is found in most of the series of Rhododendrons with large 
leaves—for example in those of arborewm, barbatum, Edge- 
worthi1, Falconert, Fortunet, heliolepis, irroratum, lacteum, ponti- 
cum, Thomsont. In contrast with this type of bud is that 
in which there is no shone The scale-leaves overlap with 
vernation that becomes convolute and the young foliage-leaves 
continue the ptyxis and vernation of the scale-leaves and 
the more external are convolutely wrapped ‘round the inner 
ones in a normal succession. Often the delimitation of the 
last scale-leaf from the first foliage-leaf is not easy to determine. 
This is the type of bud that is found in most of the small- — 
leaved Rhododendrons—for instance the Lapponicum, Fragrans, 
Cephalanthum Series; in Rhododendrons with intermediate 
size of leaf—for instance the Triflorum Series ; and in larger- 
leaved forms—for instance Maddeni, Boothii, Camelliaeflorum 
Series. Rh. Valentinianum belongs in leaf-scale to the Maddeni 
Series and has thus its characteristic convolute type of bud. 
I cannot discuss here the grouping of the species of Rhododen- 
dron. I hope to deal with that question later in these pages. 
But I want to point out that this difference in bud-construction 
is primary and must be taken into account in any scheme of 
* Maximowicz, Rhododendreae Asiae orientalis (1870), 
