leaves and yellow flowers; and H. polifolium roseum, has pretty rosy-red
flowers.

H. UMBELLATUM.--South Europe, 1731. A neat, small-growing species, with
white flowers and glossy-green leaves covered with a rusty-white
tomentum beneath.

H. VULGARE.--Common Rock Rose. Europe (Britain), North Africa, and West
Asia. A widely distributed native plant, of dwarf growth, with
linear-oblong, hairy leaves, and usually yellow flowers. H. vulgare
nummularium differs in having the leaves green and sub-orbicular, with
yellow flowers. H. vulgare barbaturn is of erect habit, with silky,
hairy, oval leaves. H. vulgare mutabile bears pale rose flowers, marked
with yellow at the base. H. vulgare grandiflorum is remarkable for the
large, bright yellow flowers, and is one of the most beautiful and
worthy varieties. H. vulgare ovalifolium (_syn H. serpyllifolium_) bears
yellow flowers and ovate leaves, with the margins revolute. H. vulgare
hyssopifolium bears reddish flowers, but the colouring varies
considerably, and saffron is not uncommon.

The Rockroses are very valuable plants, in that they will succeed on
poor, gravelly banks where few other plants could eke out an existence.
They cannot withstand stiff soil, nor that at all inclined to be damp,
their favourite resorts being exposed, rocky ground, and dry, gravelly
banks. Being readily increased from cuttings, which take root well under
a hand glass or in a cool house, it is advisable, at least with the more
tender forms, to have at hand a stock, so that blanks in the shrubbery
may be filled up.