AUSTRALIAN FERNS. 73 



Elver ; but this opinion can scarcely be reconciled with the views 

 of Hooker, who appears to have founded his remarks on certain 

 specimens collected by Cunningham on the Brisbane, and Dr. 

 Mueller, in Northern Australia. As the venation and habit of 

 the Ash Island variety are very similar to the P. rupestre and P. 

 confluens of Hooker, it seems to me highly probable that all of 

 these ferns are merely forms of one species, varying according to 

 the soil, heat, and moisture of the place in which they occur. 

 Thus, for instance, the quantity of stellated hairs and tomentum, 

 as well as the size of the fronds, may be considered as influenced by 

 surrounding circumstances ; whilst probably the increased length 

 of the fronds may lead to the diminution of the fructification. P. 

 attenuatum has very smooth fronds of a linear-lanceolate shape, 

 with a well denned midrib and the veins scarcely perceptible, 

 whilst the sori are large, of a globular shape, and arranged in a 

 single row on each side of the midrib. The texture of this fern 

 is coriaceous and the petiole somewhat compressed and marginate, 

 whilst the full sized frond is generally about two feet in length. 

 Nearly allied to this, is P. Cunninghami, a New Zealand species 

 frequently associated with the preceding, but, according to 

 Hooker distinct from it. P. irioides, as well as the preceding, 

 is found principally in North-Eastern Australia, and it seems 

 scarcely to differ from P. muscefolium of the Oriental Archipelago. 

 The specific name suggests the resemblance which the fronds 

 bear to the leaves of the iris. These are sometimes three feet 

 long, of a firm, fleshy texture, very smooth, and of an elongated 

 lanceolate shape. M. Thozet, of Rockhampton, has cultivated 

 this fern with success/ but the plants which he kindly sent to the 

 writer of this article, did not seem adapted to the climate of 

 Parramatta, for they perished in the cold weather. The long 

 climbing ferns generally referred to P. pustulatum, P. membra- 

 nifolium, P. diversifoliwn, and P. Billardieri, are now united by 

 Dr. Mueller ;in one species, viz., P. scandens, a name which he 

 justly remarks is " exquisitely appropriate." In one form or 

 other this species is widely distributed in Australia, and flourishes 

 most luxuriantly in dark, moist woods. It is not so much ad- 

 mired as P. tenellwi, but as it climbs up the huge trees of the 

 forest, it is an interesting object. It may be found within a few 

 miles of Sydney, but the finest plants of the species occur on 



