Cyclopteris.
This generic name was created by Brongniart in 1828[1552] for specimens which he believed to be complete single leaves of orbicular or reniform shape similar to those of Trichomanes reniforme. The lamina is traversed by numerous dichotomously branched veins which spread from the centre of the base.
It was suspected by Lindley and Hutton[1553] that certain Cyclopteris leaves belonged to the frond of a species of Neuropteris, and some years later Lesquereux[1554] concluded that Brongniart’s genus was founded on orbicular leaflets of Neuropteris. In 1869 Roehl[1555] figured a specimen of Neuropteris bearing Cyclopteroid pinnules on its rachis. It is now universally admitted that Cyclopteris is not a distinct genus and that the specimens so named were borne as modified pinnules on the main rachis of Neuropteris and Odontopteris. It is, however, convenient to retain the name for detached leaflets which cannot be referred to the fronds on which they were borne. A specimen found by Mr Hemingway in the Upper Coal-Measures of Yorkshire and described in 1888[1556] affords a striking example of the large size attained by what was probably a frond of Neuropteris. The piece of main rachis reached a length of over 120 cm. and bore five pairs of Cyclopteris pinnules, some of which were 7 cm. long and 5 cm. broad. The complete frond must have reached a length of at least 4 metres. Fig. 370 shows some typical Cyclopteroid leaflets on the petiole of a Neuropteris frond.