THE DICTIONARY OF GARDENING, 
Thelymitra—continued. 
the anther into a broad hood, usually conspicuous from its 
dark colour. May. l long, narrow. h. variable, usually about 
lft. 1824. Syns. T. Forsteri, T. graminea, T. pauciflora. 
_ T. paucifiora (few-flowgred). A synonym of T. longifolia. 
"T, variegata (variegated). /l. purple, two to four, large ; sepals 
and petals lanceolate, shortly acuminate or acute, in, to lin. 
long, variegated. May and June. J. with a villous sheath, the 
ee usually glabrous, linear, much dilated at base and often 
undulated. ‘Stem not very stout, lft. high or rather more. 
Syns. Macdonaldia spiralis, M. variegata. 
T, venosa (veined). fl. blue, six to ten ; sepals and petals żin. to 
Zin. long; column broadly winged. April. l. long, narrow. 
Stem lft. to 2ft. high. 1826. SyN. Macdonaldia venosa. 
THELYPOGON. 
see). 
THEMISTOCLESIA (named in honour of the Greek 
statesman Themistocles). Including Centrostemma. ORD. 
Vacciniacee. A small genus (four species) of glabrous, 
villous, or pubescent, stove, evergreen shrubs, with 
slender, pendulous branchlets, inhabiting the Andes of 
Peru, Bolivia, and Venezuela. Flowers disposed in short 
racemes; calyx tube continuous with the pedicel, cam- 
panulate or obconical, the limb minutely five-toothed ; 
corolla tubular, the base or middle of the tube slightly 
swollen, the limb small, with five recurved teeth ; stamens 
ten, as long as the corolla. Leaves alternate, sub-sessile, 
rounded or cordate at base, ovate, long caudate-acumi- 
nate, coriaceous. T. coronilla, the only species calling 
for description here, thrives in a compost of turfy loam, 
peat, and sand. It may be increased by cuttings, which 
readily root in sand or soil, with or without the pro- 
tection of a glass. 
T. coronilla (small-crowned). fl., calyx short, pale green ; corolla 
dark red and shining, glabrous, narrow-urceolate or tubular and 
inflated below, obscurely five-angled ; pedicels axillary, solitary 
or in pairs. January. /. numerous, spreading and deflexed, żin. 
long, obtuse, entire, often glabrescent above, pale beneath. 
Branches stout, and, as well as the leaves, peduncles, and calyces, 
softly hairy. Venezuela, 1866. A small shrub. (1. H. n. s. 33.) 
Syn. Thibaudia coronaria (B. M. 5575). 
THENARDIA (named by Kunth in honour of his 
friend L. J. Thenard, a Frenchman, who wrote on the 
chemical physiology of plants). ORD. Apocynacee. A 
monotypic genus. The species is an interesting, glabrous, 
stove, climbing shrub, requiring similar treatment to that 
recommended for Dipladenia. 
T. floribunda (bundle-flowered). fi. pink, broad, in nearly 
umbelliform cymes; calyx somewhat five-parted; corolla tube 
$. 
very short, sub-rotate, the lobes five, broad, spreading, twisted ; 
p cels elongated. June. l. opposite, 2żin. to Shin. long. 
ranches terete, slender. A. 10ft. Mexico, 1823. 
THEOBROMA (from theos, god, and broma, food ; 
referring to the well-known produce of the seeds of 
T. Cacao). Syn. Cacao. ORD. Sterculiacee. A small 
genus (about half-a-dozen species) of stove trees, inhabit- 
ing the warmer parts of America. Flowers rather small ; 
calyx five-cleft or five-parted ; petals five, cucullate-concave 
and contracted into a claw at base, produced above into 
a spathulate hood; stamens opposite the sepals; peduncles 
axillary or lateral, one-flowered and fascicled or race- 
mosely many-flowered. Fruit often large, drupaceous, 
with a woody, five-celled stone; seeds enveloped with 
pulp. Leaves ample, oblong, undivided, penninerved or 
three to five-nerved at base. To dilate on the immense 
economic value of the seeds of T. Cacao would be beyond 
the scope of this work. It may be remarked, in passing, 
that the annual European consumption of Cacao seeds, 
in the form of chocolate, &c., is estimated at nearly 
40,000,000Ib., the Spaniards being the largest consumers. 
T. Cacao will thrive under the same treatment as that 
recommended for Ticorea. 
T, Cacao. g or Cocoa Plant; Chocolate Nut Tree. fl. 
A synonym of Telipogon (which 
- fascicled x rose-coloured, the segments lanceolate, acu- 
minate, ing the a corolla, May. fr. gier or 
ae sh, ovoid- ras _to Bin, long, + mong fifty to a 
h. 16ft. to 18ft. Trinidad, &e., 173 ma. waan rR 
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THEODOLITE. An expensive levelling instrument, 
used by land surveyors for determining important levels 
and ascertaining the relative heights of objects widely 
separated from each other. It is provided with a tele- 
scope, mounted so that it can be moved to any angle, 
and a spirit level and adjusting screws for fixing the 
instrument in its proper position when in use. If the em- 
ployment of a Theodolite is requisite in a garden, a 
surveyor generally supplies the instrument and super- 
intends its management. 
THEOPHRASTA (named after Theophrastus, the 
celebrated Greek botanist, who lived about 370-285 B.c.). 
ORD. Myrsinee. A monotypic genus. The species is a 
glabrous, stove, evergreen shrub, with robust, erect, nearly 
simple stems. It thrives in a compost of peat and loam. 
Cuttings of half-ripened shoots will root in sandy loam, 
with a surface consisting wholly of sand, if placed in 
bottom heat, under a bell glass. 
T, imperialis (imperial). A synonym of Chrysophyllum im- 
periale. 
T, Jussæi (Jussieu’s). fl. white, rather large, numerous in short 
racemes ; calyx of five ovate, erect segments ; corolla cylindrical- 
campanulate, five-lobed at apex, the lobes spreading; stamens 
five, affixed to the base of the corolla. /. sub-terminal, clustered, 
spreading, very shortly petiolate, linear-oblong, spiny-toothed, 
reticulate-nerved. h. 3ft. St. Domingo, 1818. (B. M. 4239.) 
T, longifolia (long-leaved). A synonym of Clavija ornata. 
T., macrophylla (large - leaved). A synonym of Clavija 
Reideliana. 
. smaragdina (emerald-green). 
smaragdina. 
THERA (Carpet Moths). A genus of slender-bodied 
Moths, from lin. to 1łin. in spread of front wings, 
which are grey, with a broad, brown cross-band in the 
centre. The larve feed on the leaves of Ooniferæ ; but 
seldom do appreciable harm. See also Pinus. r 
THERESIA. Included under Fritillaria. 
THERMIA. A synonym of Thermopsis (which 
see). 
THERMOMETER. An instrument used for measur- 
ing the intensity of heat; one of the most useful and 
essential in gardens, particularly in glass houses, where 
the occupants have to be subjected to temperatures regu- 
lated to meet their several requirements. An ordinary 
Thermometer consists of a fine glass tube, with a bulb at 
one end. In this either some mercury or spirit is 
placed, and, as it expands or contracts in the tube, the 
amount of rise or fall in the temperature is indicated. 
When a Thermometer is made, all air is expelled from 
the tube and the end is hermetically sealed. The space 
not filled with the mereury or spirit is thus rendered 
vacuous, or nearly so, and there is no resistance to 
the expanding substance when the temperature rises. 
A synonym of Deherainia 
Every Thermometer tube is provided with a frame of 
some sort, on which the scale of degrees is’ marked, 
to. denote the temperature which the expanding or con- 
tracting substance indicates 
general use in this country; there are two others, 
known respectively as Reaumur’s and the Centigrade ; 
the last-named is generally adopted on the Continent. 
Fahrenheit’s scale fixes the freezing-point at 32 deg., and 
the point at which water boils at 212 deg. In Reaumur’s 
seale, freezing-point is Zero, and boiling-point 80 deg. 
In the Centigrade scale, the freezing-point is Zero, as in 
Reaumur’s, but boiling-point is 100 deg. The three are, 
therefore, quite different to read, because of the spaces 
on the scales between freezing and boiling-points being 
differently divided. 
There are various kinds of Thermometers in use where 
meteorological observations are taken; many of these 
are made in special ways, for special purposes: thus, a 
Maximum registers the highest, and a Minimum the 
lowest, temperature which has been experienced since 
the indicators in either of the instruments were last set; 
Fahrenheit’s scale is in — 
epee ee ae 
