41. Like all ferns, tree ferns reproduce by means of spores developed in sporangia on the undersides of the fronds. 42. Derreen garden is particularly noted for its rhododendrons ( Rhododendron arboreum ) and tree ferns ( Dicksonia antarctica ). 43. The restored Cascade and exotic tree ferns all help to create a sense of wonder in the'Secret Garden '. 44. As in all the tree ferns , the ring is oblique and complete, not interrupted by the foot of the sporangium. 45. The nest is a bulky cup of plant fibres and scales of tree ferns saddled on a thin downsloping branch. 46. The main plant group is the collection of Australian tree ferns , some of which have lived here for 120 years. 47. Fern diversity is usually high in many areas, in areas where tree ferns provide a suitable substrate epiphytes also flourish. 48. There were roaring mountain brooks and, most peculiar, clearing rivers that flowed gently between banks garnished with 20-foot-tall tree ferns . 49. Cyatheaceae and Dicksoniaceae, together with Metaxyaceae and Cibotiaceae, are a monophyletic group and constitute the " core tree ferns ". 50. This is a fairly recent phenomenon, but one which may eventually have grave consequences for the tree fern ecosystem in Hawaii.
