636 Jesson .— On the Hairs of the Tomentum and Ovary in 
from the middle and lower part of the hair appearing as continuous rings of 
collapsed cells, the whole being devoid of contents. 
In R. Hodgsoni the leaves are described by Clarke, 1 . c., as * long- 
petioled, narrowly obovate-oblong, cinnamomeous or whitish subtomentose 
beneath’. A medium-sized leaf is about 21 cm. long by 8 cm. broad, but 
in order to examine the tomentum a young leaf was selected. In this con¬ 
dition the tomentum is of a dull cinnamon colour, granular in appearance 
and conveying none of the velvety appearance of R. Falconeri. In older 
leaves the tomentum becomes thinner and more scattered, and the individual 
hairs much smaller, till in the oldest leaves it loses all granular appearance 
and merely looks like a brown skin. This is not the case in R. Falconeri ’, 
as the tomentum never loses its felt-like appearance, though in older leaves 
A B c 
Hairs from the tomentum of Rhododendron Falconeri ( A ) and R. Hodgsoni {B and C). 
All greatly magnified. 
it may become somewhat blackish in colour. The hairs of R. Hodgsoni are 
peltate, and consist of a saucer-shaped mass of cells, having a stalk attached 
at the centre of the convex surface (Fig. E). Here also, the outermost 
cells are prolonged, but the arms are much shorter, more pointed, and 
are usually formed simply by the elongation of the outer cell, without 
further division, and are thus unicellular and not multicellular as in the 
previous case. Breitfeld 1 describes a broom-shaped, shaggy hair from the 
leaves of several species of Rhododendron, including those of Rhododendron 
Falconeri . The writer has not been able to find any such hairs on the 
leaves, but the ovary possesses a very similar type, as will be seen below. 
In considering the relation of these trichomes to the other types 
exhibited by the genus, the typical peltate form seems to be the simplest, 
and the form from which those now under consideration have sprung 
1 Breitfeld : Der anatomische Ban der Blatter der Rhodendroideae, in Engler’s Jahrb. ix (1888), 
319, Taf. vi, Figs. 3 and 6. 
