322 THE GREENHOUSE. [CHAP. XT. 



spermums, the Passion-flowers, the Rhodo- 

 chiton, the Eccremocarpus, or Calampelis, the 

 Thunbergias, the Ipomceas, and the Cobcea. 

 There are, however, several others, all of which 

 are very handsome. The greater part of these 

 require a rich light soil to make them grow 

 rapidly, and to be planted in the ground of the 

 conservatory. The Thunbergias are very liable 

 to be attacked by the red spider; and, like 

 many of the other half-hardy climbers enu- 

 merated, they may be treated as annuals, and 

 raised from seeds every year in January, 

 and planted out in June; but they do still 

 better treated as biennials, and sown one 

 year to flower the next. The Bignonias, or 

 Tecomas, are shrubby, and should be grown in 

 equal parts of loam and peat ; and this compost 

 will suit the Polygalas, and other shrubby 

 showy climbers. The Sollyas and Billardieras 

 should be grown in peat, and frequently 

 syringed to keep ofT the green fly. 



All the most beautiful hothouse climber?, 

 such as the Allamanda cathartica, the lpomcea 

 Horsfalliae, Passiflora Loudoni, and Petrel 

 volubilis, may be grown in the open air by 

 keeping their roots in heat; that is to say, it' 

 the roots are grown in a stove, or in a pit 

 heated by hot water or flues to stove-heat, the 

 stems may be brought through some opening 

 purposely contrived, and trained over a trellis 

 in the open garden. A very striking effect may 

 be thus produced by having a bed heated by 

 hot-water pipes concealed under ground, at the 

 foot of a veranda, over which these beautiful 

 tropical climbers may be trained. 



