aie 
SILVER-W HED. 
growth an indigo or purple pigment by expres- 
sion. The silvery hue of its bark, the beautiful 
contrast of the leaves, with the rich purple of the 
cone, glittering with globules of transparent 
resin, produce in combination one of the most 
striking objects which can well be imagined, and 
entitle it to precedence for ornamental purposes.” 
The noble or large-bracted silver fir, Pzcea 
nobilis, is a native of the north-west coast of 
North America, and was introduced to Britain 
in 1827. It attains a comparatively great size, 
and promises to be a valuable timber tree for 
British plantations. Its bark has a somewhat 
purplish brown colour; its leaves grow chiefly 
from the sides of the branchlets, and curve up- 
ward in a sort of sickle form, and are narrow 
toward the base, plain on the upper side, fur- 
rowed down the middle of one side, prominently 
ribbed down the middle of the opposite side, 
acute in the point, of a lightish green colour, 
silvery on each side of the rib, and about an inch 
in length ; its cones are sessile, solitary, erect, 
cylindrical, 6 or 7 inches long, and from 2 to 24 
inches in diameter, and grow on the upper sides 
of the branches ; and its seeds are about as large 
as those of the common silver fir, but lighter in 
colour, and more pointed in form. 
Douglas’s silver fir, Picea Douglasi, is also a 
native of the north-west coast of North America, 
and was introduced to Britain in 1827. It is 
hardy enough for our climate, and generally 
takes on two growths in the season. It attains 
| a considerably greater height than the common 
silver fir, and has a pyramidal outline. Its 
branches grow in regular whorls, and are at first 
rather aspiring, and afterwards horizontal, and 
slightly pendant ; its bark is dark-coloured, and 
often has a profuse sprinkling of small, elevated, 
resinous vesicles, similar to those of the balm of 
Gilead fir; its leaves are very loosely pectinate, 
narrow, straight, rather acutely pointed, from 2? 
of an inch to nearly 14 inch long, and of a light 
or vivid green colour; its cones greatly resemble 
those of the cedar of Lebanon, and are 5 or 6 
inches long ; and its seeds are about the same 
size as those of the common silver fir, but more 
oblong, and have thin, broad, shining, pale 
brownish wings. 
SILVER-WEED, — botanically Argyreia. A 
genus of ornamental, tropical, evergreen, twining 
plants, of the bindweed family. Eight or nine 
Species, principally from 10 to 30 feet high, and 
carrying either white, pink, purple, or crimson 
flowers, have been introduced to. the hothouses 
of Britain ; and several more are known. Most 
formerly belonged to the genus lettsomia. Both 
the popular and the botanical names allude to 
the silvery texture of the leaves. All the species 
are propagated from cuttings ; and most love a 
rich mould soil—Silver-weed is also a popular 
and common name of the abundant British weed 
Potentilla anserina. See the article Porentina. 
eee A small genus of herbaceous 
SIMARUBA. 
plants, of the thistle division of the composite 
order. The Virgin Mary’s species, or welted 
thistle, or curled thistle, Sidybum marianum, 
called by Linneus Carduus marianus, is a bien- 
nial weed of the banks and similar situations of 
Britain. It has commonly a height of about 4 
or 5 feet, and carries purple flowers in July. 
See the article Tuist1z. 
SIMABA. A genus of tropical ligneous plants, 
of the simaruba family. ‘The Orinoco species, 
S. orinocensis, was introduced to Britain about 
30 years ago from Orinoco. It is an evergreen, 
white-flowered shrub, of about 10 feet in height; 
and possesses, in a comparatively high degree, 
some valuable medicinal properties, and is at 
the same time decidedly ornamental. It loves a 
soil of loamy peat, and may be propagated from 
cuttings. Another species has been introduced 
from Guiana; and 5 or 6 other species are 
known. 
SIMARUBA. A small genus of tropical lig- 
neous plants, constituting the type of the natu- 
ral order Simarubese or Simarubaceze. The 
known species of this order do not amount to 
twenty, and occur principally in tropical Amer- 
ica, and are all trees or shrubs with pinnated 
leaves, a milky juice, and an intensely bitter 
bark. Several possess eminently excellent tonic 
properties ; and all seem to be more or less medi- 
cinal. Only 5 or 6 species, belonging to the 
three genera simaruba, simaba, and quassia, 
have been introduced to British hothouses ; and 
two of these are true simarubas, and furnish 
almost all the quassia-bark and quassia-wood of 
commerce. The flowers have a quinate calyx 
and a five-petalled corolla; and the fruit com- 
prises five distant, bivalve berries, seated in a 
fleshy receptacle. 
The officinal simaruba, S. officinalis, called by 
Linneus Quassia simaruba, is a native of the 
West Indies and of the tropical parts of Conti- 
nental America, and was introduced about 60 
years ago to the hothouses of Britain. It is 
called, in Jamaica, the mountain damson. Its 
stem attains the height of a tall shrub or low 
tree; its branches are alternate; its bark is 
smooth and grey, variegated with yellow spots ; 
its leaves are pinnate, and comprise each from 
two to nine smooth, deep green, acute-elliptic 
leaflets ; its flowers have lanceolate petals, of a 
yellowish white colour; and its berries are ovate, 
smooth, and black. The bark of the root is im- 
ported by druggists, from the West Indies, in 
long pieces of a few inches in breadth; and is 
used, to a considerable extent, in British medi- 
cine, under the name of quassia bark. It is 
rough, scaly, warty, of a yellow colour within, 
inodorous, and very bitter; and it contains 
malic acid, gallic acid, malate of lime, oxalate of 
lime, acetate of potash, oxide of iron, alumina, 
a volatile oil, an ammoniacal salt, and a pecu- 
liar bitter principle called quassine. It has 
powerfully tonic properties; and is administered 
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