CULTIVATION. 331 ■ 



feet, attaining the height of from eighteen to twenty 

 feetj growing only in damp places, generally gullies, 

 where the sun rarely penetrates, and where they are 

 sometimes covered with snow, as represented in the 

 vignette on the title-page. This suggests that, with 

 proper selection of situations, they might live in the 

 open air in the south and west of England, as also the 

 mild climate of Argyleshire, where shaded ravines 

 and gullies may be found similar to those of Mount 

 Wellington. 



With few exceptions. Tree Perns readily conform to 

 cultivation. A Isophila cwpensis, A. excelsa, A. Austra lis, 

 .Gyathea dealbata, 0. mediillaris, Bicksonia antarctica, 

 and B. squarrosa, grow freely in the Tetaperate House ; 

 the lofty Alsophila glaucq,, the beautiful tessellated 

 stem of Gyathea arhorea, with its crown of fine 

 fronds, and the broad shining fronds of Hemitelia 

 horrida, assume a grand appearance in the Tropical 

 House. In general, the stems of Tree Ferns are of 

 sufficient size to warrant the name of trees ; but in 

 many the thickness is more apparent than real, the 

 diameter of the woody centre being often only a few 

 inches, but in many cases covered with successive 

 productions of out-growing aerial roots, which become 

 hard and wiry, and by their interlacing, form a com- 

 pact mass; the points of these roots are, however, the 

 active feeders, and if a layer of fresh soil is occasion- 

 ally placed round the base of the stem, their growth 

 wiU be promoted, and vigour given to the plant. The 

 most fastidious Tree Fern to cultivate is Bicksonia 

 arborescens, a native of St. Helena. It was first intro- 

 duced to this country in 1 786, and many times since, 

 but refuses to become established, either in a tropical 



