1033 



THALASSIOPHYTES. 



THEA. 



1054 



rostrum, and the anterior border of the carapace notched on each side 

 of the median line for the reception of the base of the eyes, whose 

 peduncles are very short, and formed as in the Callianassce, Four 

 antenna?, slender, and inserted nearly on the same transversal line ; 

 the first pair terminated by two filaments nearly equal in length, one 

 of which however is the largest, and slightly convex towards the end. 



C. typa. Length about 10 lines. It is a native of the coasts of New 

 Ireland, where it was found by Messrs. Quoy and Gaimard. 



Ciilliatiidefi typa, magnified. 



a, antenna of the first pair ; 6, external jaw-foot ; c, extremity of one of the 

 posterior feet ; d, abdominal false feet, first pair ; e, false feet of one of the four 

 succeeding pairs ; /, marginal fringe of those false feet. 



THALASSIOPHYTES (literally ' sea-plants,' from 6<i\aooa. and 

 tyfaov) is the name given by Lamouroux to designate the vegetable 

 productions of the ocean and of its rocks and shores. 



THALASSIO'RNIS. [Dwaot] 



THALICTRUM (from the Greek edkiKTpov), a gerfus of Plants 

 belonging to the natural order Ranunculaceie. Its consists of herbs 

 which have usually a fetid smell like rue, and hence are called Meadow 

 Rues. The species have perennial roots with annual stems. The 

 flowers are corymbose, panicled, and somewhat racemose, of a green, 

 white, or yellow colour ; they have no involucre and no petals ; the 

 calyx is composed of 4 or 5 petal-like sepals ; carpels 4-15 in number. 

 Upwards of 50 species are enumerated, which are mostly natives of 

 the temperate and colder parts of the world. 



T. aquilegifolium, Feather-Columbine, has ovate stipules, placed at 

 the base of the ramifications of the petiole ; and a corymbose panicle. 

 It is a native of Europe, in woody districts of Germany, France, and 

 Italy. The stems and stamens of this plant vary in colour, sometimes 

 being greenish-white and sometime.-) purple. A variety is found in 

 Austria with dark purple stems and stamens, and is called T. a. at.ro- 

 purpureum. Another variety, T. a. formosum, has the stamens dilated 

 at the apex; whilst another has the stems green and stamens quite 

 white, and is named T. a. album. 



T. minui, Leaser Meadow-Rue, has the stem round, mealy, the 

 flowers panicled, drooping, leaflets smooth, roundish, toothed at apex, 

 glaucous, pericarps acute, furrowed. It is a native throughout Europe. 

 In Britain it is found in chalky pastures, and on the sea-coast where 

 shell-sand abounds. The T. majui, Greater Meadow-Rue, is also a 

 native of Great Britain, though rare. * 



T. Jlavwn, Yellow Meadow-Rue, has an erect branched furrowed 

 stem, fibrous roots, a somewhat corymbose panicle of cream-coloured 

 flowers, with wedge-shaped trifid acute leaflets. It is a native of all 

 districts in Europe. In Britain it occupies wet meadows, the banks 

 of rivers and ditches. It has a root of a yellow colour, and is said to 

 resemble, both in appearance and properties, rhubarb. It yields a 

 yellow dye, which may be employed for dyeing wool, and was formerly 

 used as a remedy in jaundice. Like many of the family to which 

 it belongs, it is very acrid, and produces blisters upon the skin, when 

 applied to it. 



T. foetidum, Fetid Meadow-Rue, has a simple stem, naked at the 

 base, leafy in the middle, and panicled at top ; the leaflets are obtuse, 

 toothed, aisd covered with a clammy pubescence. It is a native of 

 France, Switzerland, Russia, to., and is found in valleys and on hill 

 sides, and in the fissures of calcareous rocks. It smells more power- 

 fully than any of the species hence its specific name. 



T. Cornuti has dioecious or polygamous flowers, with club-shaped 

 filaments, obovate roundish leaflets, glaucous beneath. This is a North 

 American species, and is found on the banks of rivers and in woody 

 districts throughout the whole continent. 



THALLOGENS, a class of Plants proposed by Lindley for those 

 Flowerless Plants which are distinguished by the absence of an axial 



stem. It includes all the Cryptogamia, with the exception of Ferna 

 and Mosses. [ACBOGENS.] 



THALLUS is a botanical term used exclusively in cryptogamic 

 botany, and is generally applied to the part of the plant which bears 

 the reproductive organs, and constitutes the principal part of its 

 vegetation. 



THAMNOPHILI'N^E. [LANIAD.E.] 



THAMNO'PHILUS. [LAKIADJE.] 



THA'PSIA, a genus of Plants belonging to the natural order Umbel- 

 lifers. The species are perennial herbs, with doubly or trebly pinnate 

 leaves, large compound umbels of many rays without involucre or 

 involucella, and yellow flowers. The margin of the calyx is 5-toothed ; 

 petals elliptic, entire; fruit compressed from the back; mericarps 

 with five primary filiform ribs, three of which are dorsal, and two 

 lateral ones in the commissure, and with four secondary ribs, of which 

 the two dorsal are filiform and the two lateral ones membranous and 

 winged ; vittse in each furrow underneath the secondary ribs. 



T. villosa, Velvety Deadly Carrot, has a square glabrous stem ; tri- 

 pinnate leaves, many-parted leaflets, villous on both surfaces, lower 

 oues deflexed. This plant is found in Portugal, Spain, the south of 

 France, in Italy, and the northern coasts of Africa. 



T. silpfiium, Silphium Deadly Carrot, has a square glabrous fur- 

 rowed stem ; pinnate leaves, many-parted leaflets, all linear, hairy on 

 both surfaces, with revolute margins. It is a native of the north of 

 Africa, on the mountains of Cyrenaica, and is supposed to be the plant 

 that produced the juice called Silphium, and which was held in such 

 high repute by the ancients, that a district where it grew in abund- 

 ance was called ' Silphifera." [SiLrmuM.] 



T. Garganica, Garganiau or Greek Deadly Carrot, has a square gla- 

 brous stem ; bi- or tri-pinnate shining leaves ; segments linear, acute, 

 elongated, quite entire along the margins ; involucre with few leaves ; 

 fruit cordate at the base. This plant is a native of Calabria, Mauri- 

 tania, Greece, Sicily, Sardinia, Spain, &c. Dr. Sibthorp found it com- 

 mon in Greece and the neighbouring islands, and concludes that it is 

 the Ooircna of Dioscorides, with whose description it agrees better than 

 any of the rest. 



THAUMA'NTIAS. [ACALEPHJJ.] 



THAUMA'SIA. [AuiJE.] 



THEA, a genus of Plants belonging to the tribe Camelliece and 

 natural order Termtrumiacea;, which has been so named from the 

 slightly altered Chinese name of the dried herb which now forms the 

 almost universal beverage of the British Isles. Though now so exten- 

 sively employed, the introduction of tea into Europe is of compara- 

 tively recent origin. 



Tea however must have been used in China from very early times. 

 It is differently named in different parts of China, as Tcha, or Cha, also 

 Tha, whence we have Tsia, The, and Tea. In Persian works in use in 

 India, tea is called Cha-Khutai, or Tea of Cathay. 



The genus Thea is characterised by having a calyx which is per- 

 sistent, without bracts, 5-leaved, leaflets imbricated, the outer ones 

 smaller ; petals of the corolla 6 to 9, hypogynous, imbricated, the inner 

 ones the largest, all adhering together at the base ; stamens numerous, 

 in several rows, adhering to the bottom of the petals ; filaments fili- 

 form, anthers incumbent, 2-celled, oblong, with a thickish connectivurn, 

 cells opening longitudinally; ovary free, 3-celled; ovules 4 in each cell, 

 inserted alternately into the central angle, the upper ones ascending, 

 the lower pendulous ; style trifid, stigmas 3, acute ; capsule spheroidal, 

 2-3-lobed, 3- or by abortion 2-celled, with loculicidal dehiscence, or 

 with the dissepiments formed from the turned-in edges of the valves ; 

 seeds solitary or rarely two, in cells, shell-like testa, marked with the 

 ventral umbilicus ; cotyledons thick, fleshy, oily ; no albumen ; radicle 

 very short, very near the umbilicus, centripetal. 



The genus Camellia is usually considered to be very distinct from 

 Thea ; indeed by Cambessedes the two are separated from each other 

 by several intervening genera : they are however too closely allied to 

 allow of this separation. Distinctions have been made in the fruit of 

 the two genera. That of Thea is 3-lobed with obtuse corners and 

 opening along the middle of the lobes, that is, having the dissepiments 

 opposite to the valves, or, as expressed by modern botanists, having a 

 loculicidal dehiscence. Camellia, on the contrary, is described as 

 having its fruit obscurely triangular, without any tendency to become 

 deeply 3-lobed, with the margins of the valves turned inwards and 

 forming the dissepiments, which thus alternate with the valves, and 

 have what is now called a septicidal dehiscence. Mr. Griffith, on the 

 contrary, who is well qualified to form a correct opinion, states, from 

 examination of the Assamese tea-plant and of two species of Camellia 

 from the Khosiya Hills, that there U no difference between Thea and 

 Camellia. The dehiscence in both, he says, is of the same nature, 

 that is, loculicidal, and the only difference that does really exist is 

 simply of specific value, consisting in the fruits of the tea-plant being 

 3-lobed, of the Camellia triangular. 



The species of the genus Thea are few in number ; some botanists 

 are of opinion that even these are varieties of a single species. 



T. viridit is a large, strong-growing, almost hardy plant, with 

 spreading branches, its leaves three to five inches long, thin, almost 

 membranous, very broadly lanceolate, light green and wavy, with 

 large and irregular serratures, the flowers largo, usually solitary, mostly 

 confined to the upper axil, with 5 sepals and from 5 to 7 petals ; fruit 



