igre 
WILLOW-HERB. 
726 
root is fleshy, and rapidly decurrent, and power- 
fully stoloniferous; its stems are erect, cylindri- 
eal, reddish, smooth, leafy, and seldom branched ; 
its leaves are numerous, scattered, almost sessile, 
linear-lanceolate, acute, veiny, smooth, and of 
various breadth; and its flowers grow in long 
terminal clusters, and have a crimson-purplish 
colour, and are numerous and very showy and 
handsome, and bloom in July and August. This 
plant is a great and general favourite in all sorts 
of flower-gardens, particularly in those of careless 
or slovenly cultivators; and it thrives, and takes 
care of itself, and freely propagates, in almost all 
sorts of soils and situations, even in the smoky 
air and choked flower-plots of the largest cities. 
A variety of it called the white, 1. a. album, has 
white flowers, but occurs only in gardens. 
The great hairy willow-herb, or codlings and 
cream, 4. hirsutum, abounds in such watery 
places as ditches and the margins of rivers, 
among reeds, coarse aquatic grasses, and willows, 
in many parts of Britain. It is a true and even 
splashy aquatic, yet possesses an ornamental 
character, and thrives more or less on any com- 
mon soil; and it is all over downy, soft, and 
clammy, and exhales a transitory, peculiar, acid- 
ulous odour, very similar to the flavour of boiled 
codlings and cream. Its root is extensively 
creeping; its stems are cylindrical, leafy, abun- 
dantly branched, bushy, and from 3 to 6 feet 
high; its leaves are half-clasping, ovate-lanceo- 
late, and hairy; and its flowers grow in leafy 
corymbose clusters, and are large, and have a 
delicate purplish-pink colour, and bloom in July 
and August. A variety of it, Hh. variegatum, 
occurs wild with variegated leaves and rose- 
coloured flowers. 
The small-flowered willow-herb, Z. parviflorum, 
inhabits watery places in many parts of Britain, 
and has a highly ornamental character; and it 
commonly attains a height of about 3 feet, and 
| carries purple-coloured flowers in July and Au- 
gust.—The square-stalked willow-herb, Z. tetra- 
gonun, is a weedy-looking native of the marshes 
of Britain, and has a height of about 2 feet, and 
carries purple flowers in July.—The mountain 
willow-herb, or broad smooth-leaved willow-herb, 
E. montanum, is a weedy-looking native of the 
woods of Britain, and has a height of about 2 
feet, and carries purple flowers in June and July. 
—The rose-coloured willow-herb, or pale smooth- 
leaved willow-herb, /. rosewm, is a slightly orna- 
mental inhabitant of the marshes of England, 
and has a height of about 18 inches, and carries 
pink flowers in July.—The marsh willow-herb, 
or round-stalked marsh willow-herb, /. palustre, 
is a weedy-looking inhabitant of the marshes of 
Britain, and has a height and appearance and 
time of blooming similar to the square-stalked 
specics.—The alpine willow-herb, 2. alpinwm, is 
a small evergreen inhabitant of the margins of 
the lofty upland streams of Britain, and has a 
height of only 2 or 3 inches, and carries red 
flowers in June.—The chickweed-leaved willow- 
herb, Z. alstnifolium, is a weedy-looking native | 
of the Scottish Highlands, and has a height of 
about 6 inches, and carries pink flowers in July. 
WILLOW-OAK. See Oax. 
WILLOW - WEED, — botanically Polygonum 
Lapathifolium. An annual British weed, com- 
mon on dunghills, rich loose deep soils, and some 
marshy lands in many parts of England, but 
scarcely or not at all known in clay districts or 
on turnip lands. Its stalks are tender, succulent, 
and pale, spotted, or reddish, and have very 
swollen joints, and commonly attain a height of 
about 12 or 18 inches; its leaves resemble those 
of the common willows, but are marked in the 
middle with dark spots; its flowers have a her- 
baceous colour, and bloom from June till Sep- 
tember ; and its seeds are very bright and heavy, 
and amount to vast numbers in favourable situ- 
ations, and are highly nutritious, and are very 
grateful to partridges and other birds. This weed 
is one of the rankest, and most cumbersome, in 
the English fen districts, and is always a great 
robber of the soil wherever it grows, and makes a 
large contribution of seeds to infest samples of 
wheat, oats, and barley on corn lands; yet it 
serves well as a decoy for attracting wild ducks 
and some similar fowls, and might be made to | 
contribute its seeds in a boiled state to the feed- | 
Other popular names for it than | 
ing of hogs. 
willow-weed are snake-weed, dockleaved knot- 
grass, and pale-flowered persicaria; though these’ 
names probably confound it with other native 
polygonums. 
WIND. A sensible current in the atmosphere. 
The motions of the atmosphere are subject, in 
some degree, to the same laws as those of the 
denser fluids. If we remove a portion of water 
in a large reservoir, we see the surrounding water 
flow in to restore the equilibrium ; and, if we im- 
pel in any direction a certain portion, an equal 
quantity moves in a contrary direction, from the 
same cause; or if a portion, being rarefied by 
heat, or condensed by cold, ascends in the one 
instance and descends in the other, a counter- 
current is the visible and natural result; and 
similar effects are found to follow the same causes _ 
in the atmospheric fluid: thus no wind can blow 
without a counter or opposite current; nor can 
any wind arise without a previous derangement 
of the general equilibrium, the general causes of 
which may be stated as follows: 1. The ascent 
of the air over certain tracts heated by the sun; 
2. evaporation, causing an actual increase in the 
volume of the atmosphere; 3. rain, snow, &c., 
causing an actual decrease in its volume, by the 
destruction of the vapour. In the ‘ Philosophical 
Transactions of the Royal Society of London’ 
(vol. 51st), there is a table of the different velo- 
cities and forces of winds, drawn from a consid- 
erable number of facts and experiments, which 
give the following results :— 
