TROP^E OLUM. 



293 



no effect. There are some exotic 

 species. 



Tropje olum. — Tropceolacece. — 

 The Garden Nasturtium. The 

 well-known annual plants called the 

 Nasturtium are common in every 

 garden, and only require sowing with 

 the other hardy annuals in spring ; 

 they may be suffered to sow them- 

 selves in autumn. There were for- 

 merly on]y two kinds of the annual 

 Tropseolums, T. major and T. minor ; 

 but since 1830, several varieties have 

 been raised. One with very dark 

 flowers, is called T. m. atrosangui- 

 neum, and another with dark stripes 

 is T. m. venustum. The young 

 shoots of these plants are succulent, 

 and taste like the common land cress, 

 the botanical name of which is Nas- 

 turtium, and hence they have received 

 their popular name. Besides the 

 hardy annual kinds, there are several 

 half-hardy species, most of which are 

 kept in the greenhouse. The best 

 known in these is Tropceolum tri- 

 colorum, with red, black, and yellow 

 flowers, which has tuberous roots, 

 and such very weak and slender 

 stems, that it is found necessary al- 

 ways to train them over a wire frame, 

 as they are quite unable to support 

 themselves. In Paxton's Magazine 

 of Botany it is stated, that the tuber 

 of the root should not be buried, but 

 only placed on the surface of the soil, 

 so that the fibrous roots may pene- 

 trate it. This, he says, will enlarge 

 the bulb or tuber in " a truly asto- 

 nishing manner," and though the 

 plants will not appear healthy the 

 first season, they will afterwards be- 

 come extremely vigorous. He also 

 recommends using double pots for 

 these plants, and lilling up the inter- 

 stices with river sand, which should 

 always be kept moist. T. brachy- 

 ceras may be treated in the same 

 manner ; and it would probably suc- 

 ceed with T. tuberosum, a species 



which it is very difficult to throw into 

 flower under ordinary treatment ; 

 but which grows best in the open 

 ground, in rich soil, and with plenty 

 of air and light. T. peregrinum, 

 the Canary Bird flower, was formerly 

 considered a greenhouse plant, but it 

 is now found much better to treat it 

 as a half-hardy annual, raising the 

 seeds on a hot-bed and planting them 

 oyt in May, near some trellis work, 

 or other support, which the plant will 

 soon cover in the most graceful man- 

 ner, producing thousands of its ele- 

 gant fringe-like pale yellow flowers. 

 For the culture of Tropceolum pen- ' 

 taphyllum, see Chymocarpus. 



True Service. — Py'rus Sorbus, 

 or Sorbus domes tica. 



Trumpet Flower. — See Bigno- 

 nia and Tecoma. 



Tuber. — Tubers closely resemble 

 in their nature what are called solid 

 bulbs or corms, and appear to be re- 

 servoirs of nourishment which have 

 been laid up by nature for the sup- 

 port of the infant plant. Some 

 tubers have numerous buds in differ- 

 ent parts of their substance, like the 

 potato, and others have only buds in 

 the upper part like the Dahlia, and 

 Ranunculus. 



Tuberose. — See Polianthes. 



Tulip See Tulipa. 



Tu x lipa.— Tulipacece.— The Tu- 

 lip. The greater part of the Tulips 

 grown in gardens are varieties of one 

 species, Tillipa Gesneriana, a na- 

 tive of the Levant ; but there are 

 several other distinct species. One 

 of the most beautiful of these is the 

 wild French Tulip, T. sylvestris, 

 which is most elegantly shaped, of a 

 beautiful yellow, and very fragrant, 

 and which is occasionally found wild 

 in England. T. Sculus solis is an 

 Italian species, and T. prcecox, Van 

 Thol's Tulip, is a dwarf plant that 

 flowers very early in the season, ge- 

 nerally in March or April. Besides 



