OP ORNAMENTAL EXOTIC PLANTS. 
165 
OTHER SPECIES OP SEMPERVIVUM. 
S. SMITHII Sims. 
This species was found at the same time as the last by Professor Smith in the Island of Teneriffe. It is a 
small deciduous shrub, with spreading branches, which are extremely prolific in flowers. The leaves are spotted 
on the underside only, and when they fall off, a scar is left on the stem, on which is a row of stiff hairs. These 
hairs increase in length as the stem elongates, so that when the plant is required of a considerable size, the stem is 
quite hairy. The species was introduced in 181'5. 
S. ARBOREUM Lin. 
This species, which is the oldest of the genus in our greenhouses, having been introduced before 1640, is 
generally called the Tree Houseleek. It has very showy flowers, which, however, do not appear every year ; and 
its leaves are rather ornamental, having a delicate white margin. In its native country this plant grows to the 
height of from seven to ten feet, with a stem as thick as a man’s arm. It is most abundant in Greece, but it has 
also been found in Portugal, Barbaiy, and in the Island of Cyprus. 
S. TORTUOSUM Ait. 
This is a shrubby plant of low growth, producing numerous fleshy evergreen leaves growing close together ; 
and its flowers, which are of a brilliant yellow, glitter like little stars, and bear more resemblance to those of the 
different kinds of Sedimi than to those of the Houseleek. It is a native of the Canary Islands, and was introduced 
in 1779. 
S. ARACHNOIDEUM Lin. 
This species, which is frequently found in old greenhouses, is generally known there by the name of the 
Cobweb Sedum, having been originally supposed to belong to that genus. When not in flower it has a very 
singular appearance, as it grows in tufts like the common Houseleek, and the tops of the leaves being woolly, 
when they expand “ they carry this woolly substance with them, which being thus extended, assumes the appear- 
ance of a cobweb.” The species is a native of the Alps of Europe and the Pyrenees, and it was introduced in 
1699. The flowers differ from those of most of the other species of the genus in being of a deep pink or bright 
rose-colour. 
S. MONANTHES Ait. 
This species, which is a native of the Canary Islands, is remarkable for having only one flower on each 
peduncle, from which peculiarity it was formed into a new genus by Haworth, under the name of Monanthes 
polyphylla. 
S. URBICUM Horn. 
This species was one of those discovered by Professor Smith on the roofs of houses in Teneriffe, and it is 
remarkable for its very large, dense, pyramidal panicle of flowers. 
S. CALICIFORME Maw. 
This is a very singular plant, and according to the description in the Botanical Register, “ the leaves are 
glaucous, fleshy, very blunt, with a thin curled whitish edge. Before flowering they are so placed as to represent 
a small chalice, whence the name has been taken. The flowering stem appears to be glabrous, but the pedicels 
and the leaves of the calyx are sparingly covered mth flne transparent glandular hairs. The flowei’s are bright 
yellow, with filiform petals, and a single row of stamens of the same colour as the petals, and about half their 
length.” This was another species found by Professor Smith in the Island of Teneriffe. 
