CoLENSO. — On the Tree-Ferns of Neiv Zealand. 253 



but 1. This last fern is much more rare, and affects a higher 

 altitude than the others, having been only met with by me in 

 the Faijus forests of the Euahiue mouutaiu range, 2,000 feet 

 altitude and upwards. Of all the genera, Dickmnia is the most 

 common, especially in the southern parts of this island. Most 

 of the species are endemic ; one or two of them are stated to 

 inhabit Tasmania and Australia ; and the most striking and 

 distinct one of all, Cijathea dealbata (the " Silver-tree-fern"), is 

 said to be found in Lord Howe Islands, in latitude 32° S., 

 between the North Cape of New Zealand and Sydney. 



They are usually of a single stem, erect and columnar, and 

 devoid of branches, with a spreading crown of large regular 

 and elegant palm-like fronds, gracefully radiating from the top 

 and forming a living circle. In some species, especially of 

 Cyathea, {e.g., C. meduUaris, Forst., and C. poh/7ieuron, Col.,) their 

 fronds attain to a very large size ; I have measured them 15-20 

 feet long and proportionately broad ; when large they are grace- 

 fully arched ; when small are often extended, and nearly plane. 

 Sometimes, however, their stems are inclined, others are 

 gradually curved, and others drooping — particularly when 

 springing from the sides of a declivity or ravine, or when over- 

 hanging a stream. They are of various heights and thicknesses, 

 some species being taller and slenderer than others, ranging in 

 height from 6 to 45 feet, and in thickness from 4 inches to 

 2 feet: only one species, however, {IHchsonia fibrosa, Col.,) 

 attains to the maximum thickness ; while Vicksonia. squarrosa, 

 D. (jraciUs, and most of the species of Cyathea and of Hemitelia 

 are among the tallest. Our snigle known species of Alsophila is 

 the shortest, and is sometimes stemless. 



They are very rarely met with bearing branches ; I have, 

 however, seen a few 2-branched, and two specimens 8-branched ; 

 and occasionally 2, 8, or 4 springing closely together from the 

 ground, as if fascicled below at the base. 



Sometimes their trunks are quite clean, and devoid of 

 epiphytal vegetation ; more commonly, however, they are 

 clothed with a dense mass of epiphytes ; the stems of 

 some species, when clear, often present a neat appearance 

 throughout, from the regularity of the broken bases 

 of their stipites, which add much to their beauty ; while 

 others show no such remains, but, instead, a dense and ever- 

 increasing mass of hardened surface rootlets, which generally 

 assume a pretty even appearance, growing circularly around 

 the stem after the manner of bark, but now and then shooting 

 downwards irregularly in long shaggy masses ; this last feature, 

 hoAvever, generally pertains to the lower side of curved stems. 

 And while on some trunks there are few or no withered fronds 

 hanging from above beneath the living crown of the fern-tree, 

 others are completely enveloped in their old pendulous fronds, 



