BOG. 
ists; and ten of these have been introduced to 
Great Britain. The inhabitants of the West In- 
dies call the species which grow in their country 
hogweed, and ascribe to them many excellent 
virtues. The tuberous-rooted species is reputed 
to possess the properties of a purgative. One of 
the species earliest introduced from Jamaica 
sends out many diffused stems of about 18 inches 
in length; it has small roundish leaves at each 
joint of the stem; and its flowers have a pale 
red colour, and are produced in a very scattered 
manner upon long branching footstalks from the 
wings of the leaves, and from the ends of the 
branches. Another of the early introduced spe- 
cies sends out several stems from each root; and 
these acquire a length of 5 or 6 feet, trail over 
all kinds of plants in their immediate neighbour- 
hood, and are much ramified ; the leaves are 
heart-shaped, and grow in mutually opposite 
pairs, on long footstalks at the joints of the 
stems; and the flowers are yellow, and grow in 
loose umbels at the extremity of the branches. 
B. excelsa is an undershrub of about 5 feet in 
height from South America; B. scandens is the 
climbing species we have just noticed, from the 
West Indies; B. diffusa, B. procumbens, B. hirsuta, 
and B. viscosa, are trailing evergreens, of about 
a foot or 18 inches in length, from India, Jamaica, 
and Peru; and the other introduced species are 
herbaceous evergreens, of from 1 foot to 3 feet in 
length, from India, Spain, and South America. 
BOG. A superficial and quite recent geognos- 
tic formation of alluvial earths and dead herba- 
ceous vegetation, soft, watery, and antiseptic, 
occasionally intermixed with dead trees or tinc- 
tured with metallic oxides, and varying in me- 
chanical character from pulverulent or gravelly 
peat to spongy and agueous moss. One well- 
defined variety of it occurs principally on the 
sides of mountains, and sometimes on not very 
retentive substrata in low-lying districts, and 
may be called mountain bog. This consists 
chiefly of the decayed roots and stems of heath 
and coarse grasses, but contains some earthy 
matter; it is of a dark brownish-black colour, 
and produces heath and coarse grasses; and it 
varies in depth from a few inches to three or 
four feet. Another well-defined variety was 
formed on the site of lakes, or of prolonged or 
frequent over-floodings of comparatively tranquil 
water, and may be called lacustrine bog. This 
| consists of the decayed roots and stems of aquatic 
plants, contains a considerable proportion of both 
earthy-and animal matters, is of a blackish col- 
our, and generally, in its natural state, produces 
coarse aquatic plants. The fens of Lincolnshire, 
Cambridgeshire, and Norfolk, consist principally 
of lacustrine bog, and. aye the most profitable 
kind of boggy surface on which the British geor- 
gist can operate. A third well-defined variety 
of bog is the well-known kind called flow or 
fibrous bog, and often regarded as comprising all 
the varieties of true bog. It consists chiefly of 
numerous species of decayed or decaying moss- 
plants, with a great predominance of Sphagnum 
obtusifolium ; it is deep, wet, and spongy, re- 
markably antiseptic, and quite or nearly free 
from earthy ingredients; and, though sometimes 
occurring on the sides of mountains which have 
a retentive subsoil, it exists principally in low 
flat situations, and appears to have, in many in- 
stances, grown upon the surface of lacustrine 
bogs. This variety constitutes Lochar Moss in 
Dumfries-shire, Chat Moss in Lancashire, and the 
enormous and many-membered Bog of Allen in 
Ireland ; it has engaged the attention of the 
most eminent georgists, with a view to its re- 
clamation; and it is bog par excellence, or the 
only variety of moss formation speculated upon 
in the vast majority of schemes which have been 
promulged, during the last half century, for bog 
improvement. 
When any part of the surface of the earth — 
is so barren as not to produce plants which 
grow by striking root in the soil, some of the 
coriaceous lichens and smaller bryums and hyp- 
nums, which have no rostel to send into the 
soil, but lay hold on the surface with their 
small fangs, and obtain their whole nourishment 
from air and water, first occupy the ground ; 
and these little vivacious and persistent crypto- 
gams usually thrive and multiply with a rapidity 
proportioned to the constancy, abundance, and 
stillness of the plashes and ponds of water spread 
athwart the surface. When a considerable and 
permanent supply of water exists, cushions of 
bryums and hypnums, but especially of Bryuwm 
palustre, begin to form over the original growths, 
and serve as dams to detain more water. The 
Sphagnum obtusifolium, in its several varieties, 
then occupies the hollows; some very branched 
kinds of lichen grow thick on every hillock ; 
some of the other parasitical and aqueous musci 
and lichens lend their aid to the accumulation ; 
and thus, in the low, flat, unproductive districts 
of cold and rainy countries, wherever water is 
stagnant and husbandry neglected, a thick stra- 
tum of living moss is formed, which, by rapid 
reproduction above and constant decay below, 
speedily creates an expanse of bog. 
When the parasitical plants have formed a 
spongy mass of sufficient thickness to retain a 
permanent and plentiful supply of water, and 
especially when they have effected some degree 
of decomposition in the lower portion of the 
mass, they become a fit soil for sturdier and 
more accumulative marshy plants of our country, 
phzenogamous as well as agamous. The three 
marsh species of cotton grass, in particular— 
Eriophorum polystachyon, LE. angustifolium, and LH. 
pubescens—very speedily appear and flourish, and 
are always found in the softest and wettest parts 
of bogs, the last in England, and the other two 
in both England and Scotland. Several species 
of rushes—especially Se¢rpus cespitosus, S. pauci- 
florus, S. caricinus, S. rufus, Isolepis setacea, and 
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