CHAP. XLI. LEGUMINA‘CEX. ROBI‘’NIA. 611 
young, but as it grows old they spread out hori- — 
zontally. They are armed with strong hooked 
prickles, and not with spines or ligneous thorns ; 
the former being only attached to the bark, like 
the prickles of the common rose or the bramble; 
and the latter proceeding from the wood, like the 
spines of the hawthorn, cockspur, and other 
thorns. The leaves of the robinia are composite, 
the leaflets being sessile, and 8, 10, or even 12, 
with an odd one. Their texture is so fine, and 
their surface so smooth, that the dust which falls 
on them will hardly lie; which last circumstance 
renders the tree particularly eligible for planting 
along road sides, in the neighbourhood of towns, 
or in great thoroughfares. The flowers are disposed 
in pendulous bunches, white or yellowish, and are most agreeably fragrant : they 
are succeeded by narrow flat legumes, about 3 in. long, each containing 5 or 6 
small seeds, which are commonly brown, but sometimes black. These seeds, 
when taken out of the pod, and exposed to the air, will hardly retain their vege- 
tative properties two years, but, when kept in the pod, they will remain good a 
year longer ; and, when the pods are buried 5 ft. or 6 ft. under the surface, in 
dry soil, they have been known to keep 7 years, without losing their vitality, 
and would probably retain it fora much longer period. The dimensions of the 
tree, in its native country, vary much with the soil and climate in which it 
grows. In Kentucky, the tree sometimes attains the height of 70 ft. or 80 ft., 
with a trunk 4 ft. in diameter; but it does not arrive at half that size at Harris- 
burgh, in Pennsylvania. On the trunk and large limbs of the old robinias, the 
bark is very thick, and deeply furrowed; but on the young trees it is com- 
paratively smooth for the first 10 or 15 years. The young tree, till the 
trunk attains the diameter of 2in. or 3in., is armed with formidable prickles ; 
but these disappear altogether as it grows old, and they are wanting, in some 
of the varieties, even when they are young. The wood, which is commonly 
of a greenish yellow colour, marked with brown veins, is hard, compact, and 
susceptible of a bright polish: it has a good deal of strength, and is very 
durable; but it has not much elasticity, and is somewhat liable to crack. The 
tree has one property almost peculiar to it, that of forming heart-wood at 
a very early age, viz. in its third year; whereas the sap-wood of the oak, 
the chestnut, the beech, the elm, and most other trees, does not begin to 
change into heart, or perfect, wood, till after 10 or 15 years’ growth. (Michw.) 
In Britain, in the neighbourhood of London, the Robinia Psetid- Acacia some- 
times attains as great a height as it does in any part of America; but, north of 
London, it is as small as it is in the north-east of Pennsylvania, or smaller. 
It grows with great rapidity when young ; plants, in 10 years from the seed, 
attaining the height of from 20 ft. to 30 ft., or even 40 ft.; and established 
young plants producing shoots 8 ft. or 10 ft. long in one season. When the 
tree has once attained the height of about 40 ft. or 50 ft., it grows very slowly 
afterwards; but, whatever height it attains, there are very few specimens to be 
met with in England, that have more than 30 or 40 cubic feet of timber in 
the trunk. At 50 or 60 years of age, the trunk is not greatly increased in 
girt; but at that age the branches often contain as great a bulk of timber as 
the trunk, though, from not being straight, that timber is comparatively of 
little value, except for fuel. The greatest bulk of timber contained in any 
robinia that we have heard of is in one at Taverham, in Norfolk, which 
contains 894 cubic ft. (Withers’s Treat., p. 234.) It stands among some 
silver firs, which are presumed to be about the same age, and which contain 
nearly 3 loads (about 150 ft.) of timber each; thus affording a tolerable cri- 
terion of the comparative rate of growth of the two trees. The trees of this 
species, and of several of its varieties, in the garden of the Horticultural 
Society, and in the arboretum of Messrs, Loddiges, have attained the 
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