TH R 



OR, BOTANICAL DICTIONARY. 



THU 



669 



on the skin. It is a shrub, rising with a tortuous stem to 

 about the length of ten feet, and emitting several twisting and 

 climbing branches upon the neighbouring trees. The bark 

 is rough and grayish, and the wood white and spongy. 

 Native of Guiana. 



Thorn Apple. See Datura. 



Thorn, Black. See Prunus. 



Thorn, Box. See Lycium. 



Thorn, Christ's. See Rhamnus. 



Thorn, Cockspur. See Cratcegus. 



Thorn, Glastonbury. See Crataegus. 



Thorn, Goat's. See Tragacantha. 



Thorn, Haw. See Crat&gus. 



Thorn, Lily. See Catesbcea. 



Thorn, White. See Crataegus. 



Thorough Wax. See Buplcurum. 



Thouinia; a genus of the class Pentandria, order Mono- 

 gynia. GENERIC CHARACTER. Cater : five-leaved, per- 

 manent; leaflets roundish, three outer thicker, wrinkled, 

 naked, two inner membranaceous at the edge, silky at the 

 back. Corolla: one-petalled, bell-shaped, plaited, twice as 

 long as the calix, five-cleft; the segments very blunt, hispid 

 on the outside, with very frequent rigid fulgid bristles within 

 and along the edge, between the plaits smooth, tomentose, 

 oiliate at the top. Stamina : filamenta five, round, naked, 

 twice as long as the corolla, declining; antherse incumbent, 

 cordate, two-lobed, smooth. Pistil: germen ovate, very 

 hairy, superior; style length, form, and situation, of the 

 stamina; stigma simple, obtuse. Pericarp: drupe globular, 

 size of a plum, supported by the permanent calix. Seed : 

 triangular, somewhat ovate. ESSENTIAL CHARACTER. 

 Corolla : one-petalled, bell-shaped, hispid on the outside. 

 Style: simple. Drupe: coriaceous, of two cells, each two- 

 seeded. The only known species is, 



1. Thouinia Spectabilis. Leaves scattered, obovate-lan- 

 ceolate, obtuse, very smooth, with a stout midrib, quite 

 entire, often emarginate ; petioles short, channelled, when 

 young silky ; stipules none ; flowers axillary, solitary, large, 

 and handsome, nodding a little, on roundish peduncles, 

 thickened at the top, silky towards the base, having in the 

 middle two small acute, silky, opposite bractes. It is a tree, 

 with a hard wrinkled bark : the branches are round, silky 

 towards the top, terminated by leaves and flowers in bundles. 

 Commerson describes the fruit as a drupe; but Jussieu and 

 Lamarck consider it as a two-celled capsule, with two seeds 

 in each cell. Native of Madagascar. 



Thrift. See Slatice. 



Thrinax; a genus of the class Hexandria, order Monogy- 

 nia. GENERIC CHARACTER. Calix: spathe universal com- 

 pound ; spadix simply branched, imbricate, with proper 

 spathes in decussated spikes; perianth minute, six-toothed. 

 Corolla: none. Stamina: filamenta six, short, filiform, in- 

 serted into the base of the germen ; antherce large, (larger 

 than the pistil,) erect, bifid at the base and top. Pistil: ger- 

 men half inferior, ovate, surroundsd by the calix; style thick- 

 ish, short; stigma widish, compressed, retuse, emarginate. 

 Pericarp : berry one-celled, naked. Seed : a single kernel 

 covered with a bony shell. ESSENTIAL CHARACTER. Calix: 

 six-toothad. Corolla : none. Stigma: funnel-form, oblique. 

 Berry: one-seeded. The only known species is, 



1. Thrinax Parviflora; Palmeto Royal, or Palmelo Thatch. 

 Fronds terminating, palmate-plaited, from one to two feet 

 long; divisions lanceolate, nerved, and marked with lines, 

 rigid, almost equal ; stipes longer than the leaves, round, 

 flatted, smooth, flexile, unarmed; spadix terminating, almost 

 upright, two or three feet long; panicle branched; branches 



alternate, subdivided, spreading; branchlets or spikes decus- 

 sated, opposite, or in threes; flowers pedicelled, opposite, 

 or in threes, placed on the rachis, small, hermaphrodite; 

 berry roundish, the size of a small pea, almost juiceless ; 

 kernel white within, red in the middle ; trunk from ten to 

 twenty feet high, swelling at the base, unarmed. Browne 

 says, that this tree covers whole fields in many parts of 

 Jamaica; that it grows both in the rocky hills, and low moist 

 plains near the sea, but seems to thrive best in the former. 

 It shoots by a simple stalk, and rises generally from four or five 

 to ten or fourteen feet in height. It is always furnished with 

 leaves in the form of a fan, sustained by slender compressed 

 footstalks; and bears a great abundance of small berries, 

 which serve to feed both the birds and beasts of the woods. 

 The trunk seldom exceeds four or five inches in diameter : 

 and the timber is much used for piles in wharfs and other 

 buildings erected on the sea-shores, as it stands the water 

 well, and is never touched by the worms. The footstalks of 

 the leaves split and pared, serve to make baskets, bow- 

 strings, ropes, &c. where strength and toughness are requir- 

 ed. The leaves are called Thatch, and are used especially 

 to cover out-houses. They resist the weather for may years, 

 but are apt to harbour rats and other vermin. 



Throatwort. See Campanula. 



Thryallis; a genus of the class Decandria, order Mono- 

 gynia. GENERIC CHARACTER. Calix : perianth five- 

 parted ; segments lanceolate, erect, permanent. Corolla : 

 petals five, roundish, spreading. Stamina: filamenta ten, 

 awl-shaped, longer than the calix ; antherea roundish. 

 Pistil : germen obtuse ; style filiform, length of the stamina ; 

 stigma simple. Pericarp : capsule three-sided, triangular, 

 obtuse, bipartite ; cells opening by the exterior angle. Seeds: 

 solitary, very smooth, obovate, obtuse at the base, mucronate, 

 and curved inwards. ESSENTIAL CHARACTER. Calix : 



five-parted. Petals : five. Capsule : tricoccous. The 



only known species is, 



1. Thryallis Brasiliensis. Leaves opposite, petioled, ovate, 

 quite entire ; stipules bristle-shaped ; raceme terminating, 

 from the fork of the branches, simple, a foot long, with very 

 short bristle-shaped bractes, and filiform pedicels, longer than 

 the flowers ; flowers small, elegant, yellow ; fruits tricoccous 

 or three-grained. It is a little shrub, with round, jointed, 

 reddish branches. Native of Brazil. 



Thuja; a genus of the class Monoecia, order Monadelphia. 

 GENERIC CHARACTER. Male Flower. Calix: ament, 

 ovate, composed of a common rachis on which opposite 

 flowers are placed in a triple opposition; each flower has for 

 its base a suborate concave obtuse scale. Corolla : none. 

 Stamina : filamenta (in each floret) four, scarcely manifest; 

 antherse as many, fastened to the base of the calicine scale. 

 Female Flower on the same plant. Calix: strobile common, 

 subovate, surrounded with opposite florets, composed of two- 

 flowered, ovate, convex scales, converging longitudinally. 

 Corolla: none. Pistil: germen very small; style awl-shaped; 

 stigma simple. Pericarp: strobile ovate-oblong, obtuse, 

 opening longitudinally, with oblong scales, almost equal, 

 convex outwardly, obtuse. Seed: solitary, oblong, girt lon- 

 gitudinally with a membranaceous wing, emarginate. 06- 

 serve. This genus is very nearly allied to Cupressus. ESSEN- 

 TIAL CHARACTER. Male. Cafe: scale of an ament. Co- 

 rolla: none. Stamina : four. Female. Calix : of a strobile, 

 with a two-flowered scale. Corolla : none. Seed : one, girt 

 with a membranaceous wing. The species are, 



1. Thuja Occidentalis ; American Arbor-Vita:. Strobiles 

 smooth, with blunt scales ; branches spreading. Trunk strong 

 and woody, rising to the height of forty feet or more. The 



