AN ENCYCLOPADIA 
OF HORTICULTURE. 31 
Thrips—continued. 
other; but gardeners do not require to spend time in 
determining their identity, as the habits of all are much 
alike, and the treatment is similar for all. The genera 
are distinguished chiefly by the presence or absence of 
veins in the wings, the hairy coating on the body, and 
differences of minor importance. One of the most hurt- 
ful kinds is Heliothrips hemorrhoidalis (? H. Adonidum, 
Hal.), which injures plants in hothouses, as well as in 
winter gardens. The leaves become paler in colour, or 
turn black, and fall off. The young twigs also are fre- 
quently attacked and killed. This species is dark brown, 
with the tip of the body red-brown, and the eyes and 
limbs pale yellow. It is only about =,in. long. 
Remedies. Smoking the plants with tobacco, as for 
Aphides, or with insect-powder, washing them with 
infusion of tobacco, dipping them in soapy water, and 
keeping them for a time in the open air in summer, are 
methods that have been tried with success. There are 
no good remedies against the species of Thrips that 
feed on plants cultivated in the open air; but, fortu- 
nately, their attacks are seldom very hurtful to hardy 
plants. Choice subjects may be freed from their attacks 
by drawing the leaves between the finger and thumb, 
with sufficient pressure to crush the soft larve, but not 
to injure the leaves. 
T. Phylloreræ has been observed, in the United 
States of America, depositing eggs in the galls of Phyl- 
loxera vastatrix (see Grape or Vine Louse). The 
larve hatched from these eggs destroy multitudes of 
the Phyllozera. 
THRIXSPERMUM. A synonym of Sarcochilus 
(which see). 
THROAT. The orifice of a gamopetalous flower. 
THROAT-ROOT. See Campanula Cervicaria. 
THROATWORT. See Trachelium. The name is 
also applied to Campanula Cervicaria and Digitalis pur- 
purea. 
THRUST-HOE. Another name for the Dutch Hoe, 
a tool which the workman pushes from him when using 
Fic. 25. THRUST-HOE. 
it (see Fig. 25). It is well adapted for light work on a 
fairly even surface, and for hoeing flower-beds, &c., when 
it is necessary to loosen the surface, while standing upon 
the adjoining walk, instead of on the ‘soil. See Hoes 
and Hoeing. 
THRYALLIS (the old Greek name used by Theo- 
phrastus for Verbascum; it means a wick, and was appro- 
priate enough to the original plant, but not to the 
present). Orp. Malpighiacew. A small genus (three 
species) of stove, climbing, stellately hoary-pubescent, 
Brazilian shrubs. Flowers yellow; calyx five-parted, 
without glands; petals shortly clawed, glabrous, the limb 
fringed; stamens ten, all perfect; pedicels bibracteolate, 
articulated above the base; corymbs paniculate, axillary 
and terminal, effuse. Leaves opposite, entire, glabrous 
above, whitish beneath; petioles biglandular; stipules 
inconspicuous. Only one species is known in gardens. It 
thrives in a compost of loam and peat. Ripened cuttings 
will root in sand, under a hand glass, in heat. 
T. brachystachys disposed in short, pani- 
culate dade | not PT greta nude: glancous-green 
above, white beneath. 1823. (B. R.1162.) - 
THRYPTOMENE (from thrypto, to break or crush ; 
in allusion to the humble, Heath-like aspect of the plant). 
ORD. Myrtacee. A genus comprising seventeen species 
` mences in spring, or else the plants 
Thryptomene—continued. 
of greenhouse, Heath-like, glabrous, Australian shrubs. 
Flowers small, axillary, solitary or rarely in twos or 
threes; calyx five-lobed, persistent; petals five, persistent, 
usually connivent over the stamens; stamens five or ten, 
Leaves opposite, small, entire. The only species intro- 
duced was formerly included under Bæckea (which see 
for culture). i 
T, saxicola (rock-loving). /.-white, on slender pedicels Lin. long, 
in the upper axils. July. /. obovate-oblong, flat, obtuse or slightly 
acute, in. to tin. long, the midrib scarcely conspicuous. A. 3ft. 
to 4ft. (rarely diffuse or prostrate ?). 1824. Syn. Bæckea saxicola 
(B. M. 3160). 
THUJA. See Thuya. 
THUNBERGIA (named after of ©. P. Thunberg, 
1743-1822, a traveller in Batavia and Japan, and after- 
wards Professor at Upsala). Including Hexacentris and 
Meyenia (of Nees). ORD. Acanthacew. A genus embracing 
nearly thirty species of beautiful, stove, twining or dwarf 
and sub-erect, annual or perennial herbs, inhabiting 
South and tropical Africa, Madagascar, and the warmer 
parts of Asia. Flowers purple, blue, yellow, or white, 
shortly pedicellate, solitary in the axils, or disposed in- 
terminal racemes ; calyx annular, short, truncate or ten to 
fifteen-toothed ; corolla conspicuous, the tube ventricose, 
Fig. 26. THUNBERGIA ALATA, ag tet > Paus and Portion of — 
Flowering Branc ; eee 
curved, the limb oblique, of five rounded lobes, twisted 
to the left in bud; stamens four, didynamons near the 
base of the corolla tube; disk cushion-shaped or annular ; 
bracts at the base of the pedicels leaf-like; bracteoles 
large, the margins coherent, at least when young. Cap- 
sule thickly coriaceous, suddenly narrowed into a sword- 
shaped beak. Leaves opposite, ovate, lanceolate, cordate, 
or hastate. The best-known species are here described ; 
all are perennial, except where otherwise stated. Nearly 
all flower during the summer months, but some of the 
woody ones blossom in spring or late winter. The 
plants are of easy culture in any moderately good soil, 
but thrive best in a rich compost of fibrous loam and 
sand, to which may be added a small quantity of well- 
decayed manure. If the plants are grown in a brisk, 
moist, stove temperature, and the pots well drained, 
success is assured. Attention must be directed to 
pruning ‘unsightly or bare shoots, before growth com- 
i will become 
straggling. Propagated by seeds, and also by cuttings 
of moderately firm young wood, placed in a propa- 
gating frame, with a temperature of from 65deg. to 
70deg. T. alata and its varieties succeed under warm 
greenhouse treatment, and may readily be raised from 
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