BALFOUR—NEW SPECIES OF RHODODENDRON. 31 
Lat. 28° 20’-N. Alt. 11,000 ft. In open thickets. Shrub of 
4-6 ft. Flowers rose without markings. G. Forrest. No. 14,331. 
July 1917; in fruit. No. 14,775. Sept. 1917. 
A species clearly marked by the indumentum of the leaf 
underside. The surface appears to be dotted all over at intervals 
with little rufous-brown tufts of tomentum standing up from a 
uniform rufous-brown surface, whilst some places are bare of 
them and show a mat-green epidermal surface. From these 
bare places the tufts have fallen, and also more or less the shorter 
floccose rufous-brown hairs which give the uniform tint to the 
whole leaf under surface. The indumentum may in this adult 
state be spoken of as biform and bistrate, and it is developed in 
the following way. The young unfolding leaf has the whole 
under-leaf surface, enwrapped as it is by the revolute laminar 
halves, clad closely but not densely with whitish hairs of a 
distinctive kind. They have long many-celled stalks, the cells 
of the stalks much elongated, and then they branch, producing 
always two or three cylindric unicellular stoutish branches at each 
branching ; the branches ascend and slightly diverge, and then 
again branch in like manner, and their progeny branch, so that a 
long-branched hair is formed. Some hairs have their branching 
apparently restricted, and are therefore shorter. Mixed with 
the hairs are many greasy red short-stalked ovoid glands. Very 
soon after unfolding of the leaf the contents of these hairs long 
and short become red and the hairs look greasy, then the long 
branching hairs become agglutinated in groups and dry up to 
form the little rufous-brown tufts, the other shorter hairs between 
forming the general surface covering. In some old leaves the 
whole indumentum may have been removed, leaving the mat- 
green epidermal surface which often becomes a pale brown 
colour. 
The plant with its trunculate or cordulate oblong - oval 
apiculate leaves, glandular pedicels, floccose and glandular ovary 
with glabrous style, seems to have affinity with those species 
which I have brought together in the series Selense,* and I 
have little doubt about their relationship. The development of 
the under-leaf indumentum is, however, much greater than in 
other species of the series, where cauliflower glands and few 
shortly-branched floccose hairs are its maximum development. 
The series is apparently a prominent type on the Mekong-Salween 
divide in the extreme N.W. of Yunnan and in the Tsarong, the 
adjacent region of S.E. Tibet. 
* See Notes, R.B.G., Edin., x (1917), 97- 
