20 
THE DICTIONARY OF GARDENING, 
Tetragonia—continued : 
Fic. 17. BRANCHLET OF TETRAGONIA EXPANSA. 
ovate, triangular, or broadly hastate, 2in. to 4in. long, entire, 
obtuse or acute, the smaller Ones narrower, Australia, New 
Zealand, &c. Plant hardy, decumbent or prostrate, often extend- 
ing to several feet. See Fig. 17. (B. M. 2362.) 
TETRAGONIACEZS. Included under Ficoidew. 
TETRAGONOLOBUS. Included under Lotus 
(which see). 
TETRAGONOTHECA (from ietragonos, quadran- 
gular, and theke, a case; alluding to the four-angled 
grains). ORD. Composite. A small, North American 
genus (three species) of tall, erect, hardy, perennial herbs. 
Flower-heads yellow, rather large, solitary or loosely 
corymbose, heterogamous ; ray florets ligulate, spreading ; 
involucre explanate, with four bracts in one series; 
achenes thick, triangular, glabrous or slightly pilose. 
Leaves opposite, amplexicaul, deeply toothed or incised- 
pinnatifid. Only one species has been introduced. It 
is an interesting plant, thriving in any light, rich soil. 
Propagation may be effected by divisions, or by seeds. 
T. helianthoides (Sunflower-lik 
pedunculate, ont r ea nA ; ee an. yt hack 
diameter. August. l. Sin. to 6in. long, repandly and unequally 
t. 
toothed, or with coarse, sharp, Salient teeth. Stem 2ft. 
high, terete. 1726. de Stem 2ft. to 3f 
TETRAHIT. A synonym of Galeopsis (which see). 
yaaa A synonym of Stachys (which 
see). 
TETRAMERIUM. A synonym of Paramea 
(which see). 
TETRAMICRA (from tetra, four, and micros, 
small; in allusion to the four smaller divisions of the 
anther). Including Leptotes. ORD. Orchidew. A genus 
including about half-a-dozen species of stove, terrestrial 
or epiphytal orchids, natives of tropical America, from 
Brazil to the West Indies. Flowers mediocre, pedi- 
cellate ; sepals and petals sub-equal, free, spreading ; 
lip affixed to the base of the column, free, spreading, the 
lateral lobes shortly clawed, the middle one broad, 
ig es column erect, mite begat ton above or from 
; Faceme simple, loose; peduncle terminal, elon- 
gated, slender, rigid. Leaves linear, fleshy, semi-terete or 
Tetramicra—continued. 
very short and thick. Stems leafy, scarcely thickened, 
not pseudo-bulbous. The best-known species are bere 
described. They thrive under conditions which suit 
Sophronitis. They may be grown on blocks of Tree-fern 
stem with a little sphagnum round the collar of the plant, 
or in baskets of fibrous peat, sphagnum, potsherds, and a 
few pieces of charcoal, intermixed. Cool treatment best 
suits the species described below, and all like a light 
place; they do well when suspended near the roof of the 
cool Orchid house. They are propagated by division. 
T, bicolor (two-coloured). fi. solitary ; sepals and petals white 
linear-oblong ; lip having two very short lateral lobes, and an 
oblong front lobe nearly as long as the petals, white, streaked 
with purple on the disk; ovary very long, pedunculiform. 
Winter. i. solitary, terminating the stems, terete, recurved, 
fleshy, grooved above. Rhizome creeping, throwing up several 
slender stems about lin. long, almost cylindrical. Brazil, 1831. 
Syn. Leptotes bicolor (B. R. 1625), L. b. var. (B. M. 3734). 
T. rigida (rigid). f., sepals and petals greenish ; lip rosy, purple- 
striped, exserted, the lateral segments spreading, the middle 
one roundish-obovate, large; scape distantly sheathed, few- 
branched above or simple. March. 1. few, 4in. to 8in. long, half- 
cylindrical, linear, channelled, acuminate, recurved. h. lft. to 2ft. 
West Indies. Plant rigid. Syn. Brassavola elegans (B. M. 5098). 
T, serrulata (serrulated). fl. asin T. bicolor, but three or four 
times larger; lip white, with lines of brilliant lake radiating from 
the base, where it has two short, rounded auricles; scapes ter- 
minal, axillary, purple. April and May. l. cylindrical, fusiform, 
grooved, glaucous-green, dotted with purple. Stems sometimes 
two-leaved. Brazil. Syn. Leptotes serrulata (L. S. O. 11). 
TETRANEMA (from tetra, four, and nema, a fila- 
ment; the genus is characterised by having four stamens). 
ORD. Scrophularineæ. A monotypic genus. The species 
is a pretty, dwarf, perennial, greenhouse herb. In spring, 
it should be potted in a compost of leaf mould and sandy 
loam, and placed in the greenhouse, where it will bear a 
profusion of flowers during the greater part of the 
summer. The atmosphere of a warm greenhouse is 
necessary during winter. Propagation may be effected 
by seeds, or by divisions. 
Fig. 18. TETRANEMA MEXICANA, showing Habit and detached 
Flower. 
T. mexicana (Mexican), Mexican Foxglove. (fl. shortly pedi- 
cellate, on axillary, scape-like peduncles; calyx five-parted ; 
corolla purplish-violet, variegated with a paler colour ; stamens 
four. J. sub-radical, opposite, obovate or oblong, loosely crenate- 
toothed, angled at base, glabrous, Stems very short, or in culti- 
vation slightly elongated and ascending. Mexico, 1843. See 
Fig. 18. (B. H. 1879, 16; B. M. 4070; B. R. xxix. 52.) 
TETRANTHERA. A synonym of Litsea (which 
see). 
TETRANTHUS (from tetra, four, and anthos, a 
flower; in allusion to the four flowers—two male and 
two female—in each head). Orp. Composite. A small 
genus (two species) of dwarf, creeping, stove herbs, con- 
fined to Domingo. Flower-heads whitish, very small, on 
solitary, filiform peduncles. Leaves opposite, petiolate, 
ovate. T. littoralis, the only species introduced, is pro- 
bably now lost to cultivation 
TETRANYCHIDZ. A family of Mites, which feed 
on living plants, on the leaves of which webs are spun 
by them. The commonest and most hurtful species 1s 
Tetranychus telarius, commonly known as the “ Red 
Spider,” 
