438 PHARMACEUTICAL BOTANY 
Te'trarch. —Said of a radial fibrovascular bundle having 4 xylem and 4 phloem 
arms alternating with one another. 
Tet'raspores. —Applied to the asexually produced spores of the Floridea group 
of Red Algae on account of being formed in groups of four in the mother cell. 
Tetras'tichous.—Said of leaves when they are arranged in four vertical rows 
upon a stem. 
Thal'amus. —Another name for receptacle. 
Thal'lus. —A plant body showing no differentiation into root, stem, or leaf. 
Thennot'ropism. —Response of living matter to the stimulus of heat or cold. 
Thom.—See Spine. 
Throat. —The opening into the tube of a gamosepalous calyx or gamopetalous 
corolla. 
Thyr'sus. —A compact panicle of flowers like the Lilac or Sumac. 
Tis'sue. —An aggregation of cells of similar source, structure and function in 
intimate union. 
To'mentose. —Covered with dense, matted, wooly hairs. 
Tor'tuous.—Bent or twisted irregularly. 
To'rus.—Another name for receptacle. 
Tra'chea. —An elongated cylindrical or prismatic tube found in the fibrovascular 
system and serving for the conduction of crude sap. 
Tra'cheid. —An undeveloped trachea usually with bordered pits. 
Transpira'tion. —The giving off of watery vapor by the plant. 
Tri. —Three. 
TriadePphous. —Having the filaments in 3 sets. 
Trian'drous. —Possessing three stamens. 
Tri'arch. —Applied to a radial fibrovascular bundle having three xylem and three 
phloem arms alternating with one another. 
Tricar'pellary. —Possessing three carpels. 
Trich'oblast. —An internal hair, like those .projecting into the intercellular-air¬ 
spaces of the stems of certain Water Lilies. 
Trich'cgyne. —A slender appendage to the carpogonium. 
Trich'ome.—A plant hair. 
Trichot'omous. —Three-branched or forked. 
Trifo'liate. —Said of a compound leaf having three leaflets. 
Trimor'phous. —Possessing three kinds of hermaphrodite flowers in the same 
species, differing in the relative length of their stamens and carpels. 
Tristichous. —Three ranked. 
Triter'nate. —Applied to a compound leaf whose petiole divides into three second¬ 
ary petioles, each of which again divides into three tertiary petioles, each 
division bearing 3 leaflets. 
Trun'cate. —Ending abruptly as if cut off or flattened at the summit. 
Tu'ber. —A short excessively thickened end of an underground stem. 
Tu'bercle. —A small wart-like outgrowth upon the rootlets, roots or subter¬ 
ranean stems of various plants. 
