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thacem, containing a number of species of 

 shrubs or herbs, natives of Tropical Ame- 

 rica. They have large leaves, and red 

 fascicled or cymose flowers in a long ter- 

 minal raceme. The calyx is divided to the 

 middle into five equal short lobes , the 

 corolla is tubular and incurved, with a 

 five-lobed or two-lipped spreading limb ; 

 and the two fertile stamens are usually in- 

 cluded, and have parallel anther-cells blunt 

 at the base. The upper portion of the cap- 

 sule is without seeds, while the lower por- 

 tion, being swollen, gives it a spathulate 

 form ; it contains only four (sometimes 

 two) seeds. [W. C] 



' THYRSANTHUS. A genus established 

 for the reception of Lysimachia thyrsiflora, 

 which differs from the other members of 

 the genus by the corolla being divided to 

 its base into narrow segments, each sepa- 

 rated from the other by a minute tooth, 

 I and by the absence of the alternating 

 I sterile filaments. This name has also been 

 | applied to a genus of Primulacece now 

 called Naumbergia. [W. C] 



THYRSE (adj. THYRSIFORM). A pani- 

 cle whose principal diameter is in the 

 middle, between the base and apex. 



THYRSEFLOWER. Tliyrsacanthus. 



THYRSODIUM. A genus of Amyridacece, 

 consisting of trees, natives of Brazil, 

 Guiana, etc. The flowers are dioecious or 

 polygamous. The male flowers have a 

 bell-shaped calyx, with five sharply-pointed 

 segments, five petals inserted into the tube 

 of the calyx, and a rudimentary ovary with 

 a two-lobed stigma. The female flowers 

 and fruit are not known. [M. T. M.] 



THYRSOID. Thyrse-like. 



THYRSOPTERIS. A very handsome 

 Juan Fernandez plant, belonging to the 

 tribe Cyatheinece of Polypodiacece. It is a 

 curious large-growing fern of herbaceous 

 habit, with large supradecompound fronds, 

 elevated on stipes four to five feet long, 

 and as thick as a walking-stick ; the leafy 

 portion being four to five feet long, and 

 the lowest pinnas about two feet. They 

 are remarkable for producing, on the same 

 frond, distinct contracted fertile and leafy 

 barren portions, the fertile parts being en- 

 tirely reduced to rachiform segments, each 

 terminating in a large globose spongy re- 

 ceptacle, surrounded by a globose invo- 

 lucre, nnd so placed that they form thyr- 

 sifonn pa licles. The veins are free. Among 

 cyathcaceous ferns it is at once known by 

 the distinct character of the sterile and 

 fertile portions of the frond. [T. M.] 



THYRSULA. The little cyme which is 

 borne by the greater part of labiates in 

 the axils of their leaves. 



THYSANELLA. A genus of Polygona- 

 cece founded on Polygonum fimbriaium, a 

 native of Georgia. It is a smooth branched 

 herb, with erect rod-like stems, and nar- 

 rowly linear elongate acute sessile leaves ; 

 the ochreae truncate, with long hairs. The 

 flowers are polygamo-dioecious, in spikes 



arranged in a panicle, with densely imbri- 

 cated ochreate bracts, which are obliquely 

 truncate with an awn-like point. The peri- 

 anth is five-leaved, with scarious and frin- 

 ged margins, the two outer leaves between 

 heart-shaped and arrow-shaped, enlarged 

 after flowering; stamens eight; styles 

 three, with simple stigmas. [J. T. S.] 



THYSANOCARPUS. A genus of Cruci- 

 ferm allied to Tauscheria, but the pouch is 

 not concavo-convex, the margin is much 

 more broadly winged, and in most cf the 

 species the extremity is not prolonged into 

 a beak. The obovate or orbicular pouch, 

 and the white or violet flowers distinguish 

 it from Isatis. They are natives of North- 

 western America, and consist of small an- 

 nuals, with the pouch winged, plano-con- 

 vex, or wingless and lenticular. [J. T.S.J 



THYSANOSPERMUM. A genus of Ru- 

 biacece, comprising a climbing shrub with 

 opposite leaves. The calyx and corolla are 

 both five-parted, the latter white with a 

 slender tube, its lobes overlapping one 

 another in the bud ; fruit capsular; seeds 

 numerous, winged. The species is a na- 

 tive of Hong-Kong. The generic name is 

 derived from the Greek thusanoi ' fringe,' 

 in allusion to the winged seeds. [M. T. M.] 



THYSANOTUS. A genus of Australian 

 Liliacece, with narrowly linear leaves, and 

 terminal umbels of purple flowers, green 

 on the exterior. The perianth consists of 

 six divisions, of. which the inner three 

 are broader, and fringed at the margin ; 

 stamens six (rarely three), with glabrous 

 filaments; ovary three-celled, with two 

 ovules in each cell. [J. T. S.] 



TIA. A Chinese name for Sageretia 

 theezans. 



TIAKLOU. An Indian name for Berberis 

 tinctoria, 



TIARELLA. A small genus of North 

 American Suxifragacece allied to Heuchera 

 and MiieUa, but differing from the former 

 in having ten stamens, and from the latter 

 in the calyx being almost free from the 

 slender ovary, as well as in the entire 

 petals. They are perennial herbs, with 

 simple or trifoliolate incised and serrated 

 leaves, and a leafless scape bearing a ra- 

 ceme, or a leafy stem with a panicle of 

 white flowers. Calyx bell-shaped, nearly 

 free from the ovary, five-parted; petals 

 five, small ; styles two ; capsule one-celled, 

 with two unequal valves; seeds few, sub- 

 globose. The most common species of 

 this genus, T. cordifolia, is met with in 

 the regions extending from Canada to 

 Virginia. [J. T. SJ 



TIARIDIUM. A genus of Ehretiacece 

 found in Tropical America and Asia, and 

 having the habit of H eliotr opium , from 

 which it differs in the angular tube of the 

 corolla, with a contracted five-rayed orifice, 

 and in the two-celled mitre-shaped nuts. 

 T. indicum is an astringent, and is used 

 to allay inflammation ; it is also said to be 

 beneficial in cleansing ulcers. [J. T. S.] 



