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SWAD.. 
388 
itself, and is specifically called the frutescent ; 
but it is nearly allied to the bladder-sennas, and 
was ranked as such by Linneus. It was intro- 
duced to Britain so long ago as the latter part of 
the 17th century; and it is but slightly tender. 
It has a height of about 3 feet, and carries scar- 
let flowers in June and July; and it loves a soil 
of sandy loam, and is propagated from seeds, 
SUWARROW NUT. See Burrer Not. 
SWAD. A pod or legume. The word is pro- 
vincial. 
SWAINSONIA. A genus of ornamental, ever- 
green, small, Australian shrubs, of the lotus di- 
vision of the leguminous order. Two species 
with purple flowers, and two varieties of another 
species with respectively red and white flowers, 
all about 2 feet high, and blooming in July and 
August, have been introduced to British gardens, 
They love a soil of sandy peat, and are propa- 
gated from seeds. 
SWALLOW,—scientifically Airundo. A genus 
of birds of the fissirostrous family of passerine. In 
a large sense, it comprises all the diurnal species 
of that family; and in even a smaller sense, it 
comprises not only the common swallow, but also 
the martin, the sand martin, and the salanganes. 
The bill of all, in common with that of other 
fissirostres, is short, broad, horizontally flattened, 
slightly hooked, and unemarginate, and has an 
extended commissure, so that the opening of the 
mouth is very large, and possesses eminent adap- 
tation to the catching and swallowing of insects 
while the birds are on the wing. 
The common or country or chimney swallow, 
Hirundo rustica, is a well-known, regular, very 
numerous, and very useful visitor of Britain, and 
of many other lands. Its total length is 83 
inches ; its outside tail-feathers are very elon- 
gated, and measure nearly 5 inches; its general 
plumage is slate blue and dull black ; its fore- 
head, eyebrows, and throat are red or chestnut ; 
and some parts below are pure white. It feeds 
entirely on winged insects, and hunts them 
through the air during the greater portion of 
the day, and has such power of flight as to pur- 
sue its prey for hours in succession without any 
apparent fatigue. It builds in chimneys and si- 
milar places, and forms its nest of moistened 
earth or clay mixed with bent and straw, and 
lined with feathers. Its eggs amount to four or 
six, and have a white colour speckled with ash 
and dark red, and measure 94 lines in length 
and 6} in breadth. 
Swallows are controlled in the period of mi- 
gration by the temperature of the season and the 
state of the wind; but, on the average, they arrive 
in Britain about the 10th of April, and depart 
about the middle or latter part of October. They 
come gradually or in small and successive num- 
bers, but go away in vast flocks, leaving only a 
few stragglers behind. On the coast between 
Orfordness and Yarmouth, they assemble in 
swarms in October, covering the church -leads 
SWALLOW..WORT. 
and the naked branches of trees; and they are 
then preparing to depart from the tract of coast 
whence emigration is easiest to their winter- 
retreats, and they are evidently wind-bound, for 
they abide in their gathering-place till the wind 
veers to the north-west or some other favourable 
point,—and if this happen in the night, they so 
suddenly and entirely disappear that not a swal- 
low can be seen in the morning. 
Swallows are a very useful race of birds, and 
relieve us from innumerable noxious insects 
which infest our atmosphere and prey upon our 
crops. ‘“ Whoever contemplates the myriads of 
insects that sport in the sunbeams of a summer 
evening will soon be convinced to what a degree 
our atmosphere would be choked by them, were 
it not for the friendly interposition of the swal- 
low tribe. Such would-be marksmen as shoot at 
swallows should. recollect that these birds are 
seen only during the breeding months in sum- 
mer, and that by shooting the old ones the nest- 
lings in consequence perish. Minute observers 
calculate that one of these birds destroys daily 
hundreds of gnats, flies, moths, and other insects, 
parents of the swarms of gnats and caterpillars 
which strip our gardens, and commit such waste 
upon vegetation in general. These birds, there- 
fore, should be considered as little messengers of 
Providence, and as instruments without whose 
assistance the plough and the spade would often 
be ineffectually employed. In almost every vil- 
lage in America, they are held in the same sort 
of veneration as the Egyptians show to the ibis 
of the Nile; the villagers place small square 
boxes,—some of them prettily adorned and paint- 
ed,—to induce these strangers to sojourn and 
peaceably enjoy their months of incubation. The 
late Dr. Franklin used to say, 
‘* Be kind to the swallow, 
And profit will follow.” 
SWALLOW-WORT,—botanically Asclepias. A 
genus of ornamental exotic plants, constituting 
the type of the natural order Asclepiadee. This 
order is noticed in the article AscrEPias. The 
calyx of the swallow-wort genus is five-cleft, 
small, and persistent ; the corolla is monopetal- 
ous, flat or reflexed, with a five-leaved crown, 
and a process on the inside; the pollen-masses 
are fixed by a fine end; and the stigma is de- 
pressed and blunt. About 40 species have been 
introduced to Britain from other countries,— 
principally North and South America; about 30 
more are known; and a good many which for- 
‘merly belonged to it, and have been introduced 
to Britain, are now assigned to nine other genera. 
The swallow-worts are remarkable for curious 
beauty ; and several are economical and medi- 
cinal. Most of those in British collections are 
erect, perennial-rooted, annual-stemmed herbs ; 
but a few are either tuberous-rooted or ever- 
green herbs or twiners. The majority are hardy ; 
and the rest belong variously to the greenhouse 
and the hothouse. All, with a few exceptions, 
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