As the form of the pseudo-bulbs suggests, this genus is easily propagated by cuttings. These are made about six inches long and inserted in pots of sand. After standing in an ordinary propagating-frame or moist stove for a short time young growths will appear at the nodes. When large enough they are taken up and potted in ordinary compost. Two years at least are needed for them to attain to flowering size, but this is the best method where a large number of plants are wanted. (See also under Orchids.) =Thuya=, including Biota (Arbor-Vitæ, White Cedar erroneously). _Coniferæ._ Seeds. Layers. Cuttings of green shoots in summer in a cool frame. Cuttings of ripe wood, as recommended for retinospora. The named varieties are often grafted on potted common stocks in winter or early fall. =Thyme= (_Thymus vulgaris_). _Labiatæ._ Seeds and divisions. =Thyrsacanthus=, Odontonema (Thyrse Flower). _Acanthaceæ._ Seeds; cuttings made in spring, and placed in a close, warm frame. =Tiarella.= _Saxifrageæ._ Seeds and divisions. =Tigridia= (Tiger Flower). _Irideæ._ May be increased by seeds, or generally by offsets. =Tilia= (Basswood, Linden, Lime-tree). _Tiliaceæ._ Stocks are grown from stratified seeds. Layers may be made, and cuttings may be employed, but the named sorts are usually grafted on strong common stocks. Mound-layering is sometimes practiced. =Tillandsia.= _Bromeliaceæ._ May be increased by seeds, and by suckers which should be allowed to grow large before being detached from the parent and should then be inserted singly in pots, in a compost of loam, peat, and leaf-mould. Keep moderately moist and well shaded. _T. usneoides_ is the "Spanish Moss" of the south; rarely propagated, but may be grown from seeds or divisions of the moss. =Tobacco.= See Nicotiana. =Tolu Balsam-tree.= See Myroxylon. =Tomato= (_Lycopersicum esculentum_). _Solanaceæ._ Seeds, usually started under glass. Cuttings of growing shoots. =Torenia.= _Scrophularineæ._ Seeds. Cuttings, in a warm frame. =Torreya.= _Coniferæ._ Increased the same as Thuya and Retinospora. =Trachelium= (Throatwort). _Campanulaceæ._ Seeds and cuttings. =Trachelospermum=, Rhynchospermum. _Apocynaceæ._ Seeds. Firm cuttings, in a frame. =Trachycarpus.= _Palmæ._ Seeds and suckers. =Tradescantia.= _Commelinaceæ._ Usually by cuttings; also by seeds and divisions. =Trapa= (Water Caltrops). _Onagrarieæ._ Seeds. =Tree of Heaven.= See Ailanthus. =Trichilia.= _Meliaceæ._ Seeds. Cuttings of the ripened wood, with leaves, or under glass in heat. =Trichopilia.= _Orchideæ_. Divisions of the plants. (See also under Orchids.) =Trichosanthes= (Snake Gourd). _Cucurbitaceæ._ Seeds, either in-doors or out. =Tricyrtis.= _Liliaceæ._ Seeds rarely. Offsets and divisions.