The Peranemaceae was first proposed by C. B. Presl (1836) as a tribe under the Order Filicaceae Suborder II. Cathetogyratae Cohort V. Hymenophoreae and was placed between the tribes Cyatheaceae and Aspidiaceae in his system. Apparently Presl recognized the re lationships of the three tribes with Peranemaceae as a link between the other two tribes. In the past century after Presl, the arguments regarding the systematic position of the Peranemaceae has been chiefly centered around Dicksonia, Cyathea, Woodsia, Dryopteris and Aspidium. The peculiar morphological characteristics of Peranemaceae have attracted the at tention of many morphologist in the last fifty years or so. As a result the circumscriptions for this group of fern have become much clearer than heretofore. The current general opinion supports the Peranemaceae as consisting of Peranema Don, Diacalpe B1. and Acrophorus Presl, although the status of the three genera remains an open question.

      Early in 1940 R. C. Ching proposed for the first time  Peranemaceae as a separate

family, but not until 1978 he formally declared the validity of the family by citing the tribe Peranemaceae Presl as reference, with Peranema, Diacalpe and Acrophorus as its legitimate constituents. Phylogenetically, Peranemaceae is derived from the Dryopteroid stock and its relationships with Dryopteridaceae and Aspidiaceae are selfevident, because they have many morphological and anatomical characteristics in common, yet it differs from both families in other important aspects, such as inferior sorus enclosed in a globose  indusium and the presence on fronds of the thick septake, often dark red hairs. On the other hand, the Peranemaceae have a number of characters in common with Cyatheaceae such as the elevated receptacle of sori, the haracteristically multicelluar hairs on the underside of the gametophyte and the antheridium provided with a divided lid cell, but markedly different in the morphology of sprangia, bilateral spores and base chromosome numbers. All in all it seems that Peranemaceae have synthesized the main characteristics of Cyatheaceae, Dryopteridaceae and Aspidiaceae as already noted by both Bower and Davie, in addition to the irown peculiarities. Fern students today generally agree upon the Cyatheoid origin of the family Dryopteridaceae, for which Peranemaceae may serve as an additional evidence.

      As to the much argued generic status of the three constituent genera of the family

Peranemaceae, i.e. Peranema, Diacalpe and Acrophorus, we maintain that they are distinct

from each other as shown in the following key. As to the systematic position of Lithoste-

gia Ching and Nothoperanema Ching, they are legitimate members of Dryopteridaceae, the

former more closely related to the genus Arachniodes than to any other genera, while the latter to Dryopteris especially the group of D. wallichiana (Spreng.) Hyl.

      Geographycally the family Peranemaceae so far known are chiefly ferns of the Asia

mainland, especially southwestern China (Yunnan, Sichuan and southeastern  Xizang),

and also upper Burma, with very a few species extending eastwardly to Malesia, Indonesia,

and the Phillippines.