CULTIVATION. 
3G5 
feet, attaining the height of from eighteen to twenty- 
feet, growing only in damp places, generally- gullies, 
where the sun rarely penetrates, and where they are 
sometimes covered with snow, and in summer the 
atmosphere loaded with vapour. 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 Ferns readily conform te 
cultivation. A Isophila capensis, A. excelsa, A. Australis T 
Cyathea dealbata, G. medullaris, Dicksonia antarctica , 
and D. squarrosa, grow freely in the Temperate House - y 
the lofty Alsophila glauca, the beautiful tessellated 
stem of Cyathea arborea, 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 
will be promoted, and vigour given to the plant. The 
most fastidious Tree Fern to cultivate is Dicksonia 
arbor escens , a native of St. Helena. It was first intro- 
duced to this country in 1786, and many times since, 
but refuses to become established, either in a tropical 
