xy 
hairs of the upper stratum 
BALFOUR—NEW SPECIES OF RHODODENDRON. 45 
Rh. sanguineum and its immediate allies have a thin under- 
leaf indumentum usually grey-white, and all the bracts fall away 
apparently at flowering. But in Rh. citriniflorum, Balf. f. et 
Forrest, one of the allies, the bistrate indumentum tends to 
become tomentose, although it does not reach copious develop- 
ment on that line. The cinnamon-coloured thick tomentum on 
the under surface of the leaves of Rh. comisteum is an evident 
mark of differentiation. 
That tomentum brings Rh. comisteum towards Rh. haematodes 
and its immediate allies, but if superficially alike the indumentum 
in the two species is structurally different, for here in Rh. 
comisteum the copious branches of the hairs of the upper stratum, 
though somewhat vesicular, curl and interweave in a loose 
fashion but without forming tendrillar-like cords, whilst in Rh. 
haematodes the somewhat dendriform branched hairs form stiffer 
and narrower branches which are much shorter. Apart from 
indumentum, however, the broader and larger leaves of Rh. 
haematodes and its umbels without persistent bracts make a 
conspicuous difference. 
There is no doubt, I think, about Rh. comisteum being in its 
right place within the circle of RA. Roxieanum, as there so here 
the many persistent leaves densely clothe the stems, which are 
clad also with a dense indumentum at first cinnamon-coloured, 
becoming grey later on the exposed stems. And then there is a 
dense coating of persistent scale-leaves and bracts intermixed with 
the foliage-leaves and visible on the stems after the foliage-leaves 
have fallen. The flower-trusses are more open at flowering than 
is the case in Rh. Roxieanum, because perhaps the outer bracts 
fall, leaving only the inner ones. The indumentum of the under- 
leaf surface outwardly identical is in internal construction a near 
approximation only to that of typical Rh. Roxieanum. There the 
become thick-walled and cord-like 
and intertwine and twist around one another like tendrils. In 
Rh. comisteum the hair-cells do not become cord-like, and are not 
markedly tendrilliform. Of the members of the Roxieanum 
series Rh. bathyphyllum, Balf. f. et Forrest, and Rh. perulatum, 
Balf. f. et Forrest, have somewhat similar indumentum, but in 
general aspect Rh. proteotdes, Balf. f. et W. W. Sm., perhaps 
presents the most striking resemblances. 
Rhododendron dasypetalum,* Balf. f. et Forrest.T 
Shrub barely 1 m. with many delicate ultimate branchings 
and short annual growths. ~Branchlets a year old about I mm. 
* Jactc, hairy—in allusion to the corolla. 
+ Rhododendron dasypetalum, Balf. f. et Forrest. — Frutex vix 1 m. altus. 
Rami ann 
otini circ. 1 mm. diam. squamis rufis stipitatis dense furfuracei, vetus- 
