50 A CONTKIBUTION TO, ETC. 



Hooker's H. ma/rginatwm, a very minute species, growing amongst 

 mosses, and H. flabellatum, with which H. nitens is now united, 

 " as the winged rachis and stipes afford no positive mark for 

 specific determination." To these must be added the cosmopoli- 

 tan H. Tmibridgense, and its variety H. Wilsoni, for although in 

 Europe they seem distinct species, " yet (Sir William Hooker 

 remarks) it often becomes difficult accurately to distinguish 

 exotic ones." These pretty little ferns are very plentiful on the 

 moist rocks of our creeks ; but the other species (H. flabellatum) 

 is generally found on the stems of our tree ferns, on which it 

 forms an exceedingly pretty object. 



The genus* Trichomanes (from ihrix, triclios, "hair," and. mania, 

 " excess") differs from the preceding genus in generally having 

 a long hair-like receptacle much exceeding the involucre, but 

 this is by no means a certain mark in all species : the involucres 

 are of one leaf, mostly entire, and of a cylindrical or urceolate 

 shape. The most common species in Australia is T. venosum, 

 which grows on the stems of tree ferns, and seldom exceeds a few 

 inches in length. Somewhat larger than this is T. anrjustatuni, 

 which was found at the Richmond River, by Mr. C. Moore, and 

 by Mrs. K. Parker, at the Kurrajong. It is said to be similar to 

 that found in the Eeejee Islands. 



Dr. E. Mueller makes only four species of Alsophila, and that 

 one which we have hitherto known as A. Macarthuri, he refers to 

 A. LeicJiardtiana, as Dr. Leichardt is said to have been the first 

 person who remarked that it was specifically distinct from A., 

 Australia. Dr. Mueller gives only one species of Dicksonia, (D. 

 antarctica), referring D. duUa to Datallia, and probably regard- 

 ing D, Youngii as a coarser form of the first species ; but he 

 states that Cyatliea meduUaris, a tree fern of some fifty feet in 

 height, has been found in the neighbourhood of Cape Otway, and 

 also C. Liiulsayana, at Roekingham Bay. "Whether the former 

 splendid fern is identical with that occurring in New Zealand and 

 Norfolk Island, remains to be proved. The genus Cyatliea is 

 nearly allied to Alsophila, but it differs in having an involucre, 

 " which is globose, inferior, membranaceous or somewhat horny, 

 at first entire and covering the whole sorus, afterwards bursting 

 from the top with a nearly circular opening, becoming cup-shaped, 

 more or less entire or lobed." To this alliance the Doctor also 



