TETRANTHERA. 
5 or 6 feet in height, have been introduced to 
the hothouse collections of Britain, from Guiana 
and the West Indies; and two other species are 
known. The two introduced species are near 
akin to the coffee-tree; and they love a soil of 
loamy peat, and are propagated from cuttings. 
TETRANDRIA. See Borany. 
TETRANTHERA. A genus of ornamental, 
evergreen, ligneous, greenish - flowered, exotic 
plants, of the laurel order. Eight or nine spe- 
cies, varying in height from 6 to 25 feet, have 
been introduced to the greenhouse and hothouse 
collections of Britain from Australia, Mexico, 
China, and India; and some more are known. 
Most of the introduced species love a soil of peaty 
loam ; and all are propagable from cuttings. The 
three-nerved and the rusty are two of the small- 
est, and need only greenhouse protection; and 
the glaucescent and Cervantes’s are two of the 
tallest, and require the heat of the hothouse. 
THETRAPELTIS. A recently discovered genus 
of ornamental tropical plants, of the vandea di- 
vision of the orchidaceous order. The sweet- 
scented species, 7. fragrans, is a white-flowered 
epiphyte, introduced 12 or 14 years ago to Bri- 
tain from Nepaul. The name tetrapeltis signi- 
fies ‘four-bucklered,’ and alludes to the form of 
the pollen-masses. 
TETRAPOGON. A curious, hardy, annual 
grass, of the chloris tribe. It constitutes a genus 
of itself, and is specifically called the villous. It 
is a native of Barbary, and was introduced to Bri- 
tain about 30 years ago; and it has a height of 
about a foot, and blooms in July and August. 
TETRAPTERIS. A genus of ornamental, 
tropical, ligneous plants, of the barbadoes cherry 
family. Two species, the box-leaved and the 
orange-leaved, both yellow-flowered, evergreen 
shrubs of about 6 feet in height, have been intro- 
duced to British gardens from Cayenne and the 
West Indies; and they love a soil of peaty loam, 
and are propagated from cuttings. Several other 
species are known. 
TETRATHECA. A genus of handsome, Aus- 
tralian, evergreen, thalamiflorous undershrubs, 
constituting the main part of the small natural 
order Tremandree or Tremandracee. They have 
a peculiarly neat appearance, and exhibit consi- 
derable resemblance to heaths. Seven or eight 
species, principally about 12 or 15 inches in 
height, mostly with purple-coloured flowers, and 
all blooming in July and August, have been in- 
troduced to the greenhouses of Britain; and they 
love a soil of sandy peat, and are propagated 
from seeds, The hairy species, 7’. hirsuta, one 
of the most recently introduced, may serve as a 
sufficient specimen of the whole. It is a light, 
open, branching bush, characterised by neatness 
and simple elegance; and is all over hairy. Its 
leaves are alternate, small, oblong-ovate, and 
hairy, and give the branchesa clothing of foliage; 
and its flowers are produced from the axils of the 
leaves, and stand on footstalks projecting at least 
THATCH. 
an inch from among the foliage, and have each 
five nearly oval petals, spread out in a star-like 
form, and are at first of a bright pink colour, but 
afterwards assume a darker hue. It requires to 
be grown in a well-drained pot, and secured 
against damp in winter. 
THUCRIUM. See Gurmanper. 
THALIA. A small genus of ornamental, blue- 
flowered, exotic, herbaceous plants, of the In- 
dian-shot family. The white species, 7. dealbata, 
is a greenhouse aquatic of 4 or 5 feet in height, 
introduced to Britain about 58 years ago from 
Carolina, and blooming in July and August; and 
the jointed species, 7. geniculata, is a hothouse, 
terrestrial, herbaceous evergreen of about 2 or 3 
feet in height, introduced about 25 years ago 
from the West Indies, and blooming in August 
and September. 
THALICTRUM. See Mzapow Ruz. 
THAPSIA. See Deapty Carrot. 
THATCH. The culms of cereal grass or the 
slender stems or fronds of other plants laid on 
the top of ricks, buildings, and other structures 
to protect them from wet. The thatching of 
ricks, both small and great, is noticed in the 
article Strack. The thatching of houses, sheds, 
and other edifices may be done in any one of 
various ways, and with any one of widely differ- 
ent materials, to suit convenience, appearance, 
durability,and other circumstances. Fern thatch, 
if obtained between the middle of September and 
the middle of October, and properly prepared and 
skilfully laid on, will last in a sunny exposure 
during 18 or 20 years, and will seldom cost more 
than about one shilling per square yard. Heath 
of a slender and pliant nature, obtained from an 
open situation, properly prepared, and laid on in 
horizontal layers or from end to end of the roof, 
and, in an elevated and airy place, or in any one 
which is free from undue closeness and humidity 
of atmosphere, will last between 20 and 30 years. 
Reeds form a very valuable and long-enduring 
thatch, and are sometimes cheaper in the end 
than any other material; but they cost compa- 
ratively very high at first, and are also thought 
by some persons to be too stubborn for common 
purposes. The thrashed straw of wheat, with 
the ears on it, is the thatch most generally in 
use throughout the plains and valleys of Britain; 
and, when well laid, forms at once a very neat, 
a quite secure, and a sufficiently or tolerably 
durable covering for most structures to which it 
is applied. Unthrashed wheat straw, without 
the ears, and provincially called reed, is the fa- 
vourite thatch in the counties of Devon, Dorset, 
and Somerset, and possesses eminent advantages 
above thrashed straw, which ought to recom- 
mend it into use in all parts of the kingdom. 
It lasts nearly as long again as common straw, 
| and does not offer the temptation arising from 
the grains of imperfectly thrashed corn, which 
induces mice and birds to infest the building, 
and to make holes in the thatch. The mode of 
ek nN ohn A at AN Fh a re Fn 
