Ericacea— Rhododendron. 281 
6. Rh. arbérewm (fig. 158).—This species is not quite hardy 
even in the most favoured localities of this country, but we 
give it a place here because it is sometimes planted, and be- 
cause some of the varieties in cultivation are probably hybrids 
between this and other species. It forms naturally a small 
tree from 25 to 35 feet high, with thick leaves having revolute 
margins, glabrous above, and clothed with silvery scales beneath, 
and large clusters of beautiful scarlet flowers. Amongst the 
multitude of varieties and hybrids attributed to this species we 
may mention, altaclarénse, a fine hardy scarlet, said to be a 
hybrid between this and Rh. Catawwhiénse. There are several 
wild forms referred here, as album, puniceum, roseum, cinnd« 
momeum, ete. This species is a native of Nepal. 
7. Rh. campanulatum.—A small shrub from 4 to 6 feet 
high. Leaves elliptical, glabrous above, pulverulent and fawn- 
coloured below. Flowers very large, campanulate, rose or 
white, spotted with purple at the base of the three upper lobes. 
This is likewise a native of Nepal, though perhaps rather 
hardier than the last. There are many varieties, flowering 
with us in March and April, and consequently often injured 
hy the frosts. 
8. Rh. maximum.—A small tree from 10 to 15 feet high. 
Its leaves are oblong-lanceolate, slightly revolute, glabrous 
above, slightly pulverulent and ferruginous beneath. Flowers 
in dense depressed terminal clusters of medium size, campanu- 
late, rose and white with a pale yellow blotch and purple- 
brown spots on the upper lobe, or wholly white. This is a very 
hardy species, a native of North America on the Atlantic 
coast from Carolina to Canada, and was introduced into 
Europe about the middle of the last century. The most 
familiar variety is Glbwm, whose flowers are of snowy whiteness. 
It has also furnished some good hybrids, amongst others Dona 
Maria, obtained in Belgium by crossing it with Rh. Pénticum. 
It is a superb and very hardy plant, equally desirable for the 
large size of its clusters and its pretty rosy flowers spotted 
with orange-red. The variety Prince Camille de Rohan, re- 
ferred to above, is thought by some to be a hybrid between this 
and Rh. arboreum, or Rh. Caucdsicum. 
9, Rh. Catawbiénse.-— This is another North American 
species, originally discovered by Mr. Fraser in the neighbour- 
hood of the source of the Catawba river in North Carolina, 
and introduced early in the present century. It is a bushy 
