Callipteris.

Brongniart[1495] instituted this genus for certain species of supposed ferns previously referred to the genera Pecopteris, Alethopteris, and Neuropteris. Callipteris is a characteristic Permian plant which is almost certainly a Pteridosperm. Zeiller has pointed out that such descriptions of fertile specimens as have been written are unsatisfactory. A few years ago, however, Grand’Eury[1496] recorded the occurrence of seeds in association with Callipteris fronds in the Autun district, and in some cases they were found attached to the pinnae and rachis. The seeds are ovoid or spherical (5–10 mm. broad) and smaller than those of Neuropteris. The drawings of fertile segments published by Weiss[1497] afford no indication of reproductive organs. Potonié[1498] figures some pinnules of Callipteris conferta in which the thick lamina is covered with sinuous grooves probably made by some insect larvae: as he suggests, similar markings may have been mistaken for the remains of sori. The occurrence of Callipteris fronds recorded by Weber and Sterzel[1499] in association with Medullosa stems in the Lower Permian of Saxony is in accordance with Grand’Eury’s conclusion.

Fronds reaching 1 metre in length, bipinnate or tripinnate, main rachis frequently exhibiting a combination of dichotomous and pinnate branching. Pinnae linear, usually crowded, decurrent on the rachis; the pinnules on the lower side of the pinnae are continued on to the rachis. Pinnules of the Pecopteroid type, entire or slightly lobed, or of the Sphenopteroid type and more or less deeply dissected ([fig. 366] C, D), the lamina of adjacent pinnules concrescent; on the lower pinnae the lamina may be continuous as in an Alethopteris pinnule. A midrib may extend almost to the bluntly rounded apex of the ultimate segments, giving off oblique, simple, or forked veins, the lowest of which arise directly from the rachis; in the Sphenopteroid forms the lateral veins are given off at a more acute angle.

A striking feature of the genus is the occurrence of pinnules on the main rachis, as in Odontopteris. Zeiller has wisely extended the application of Callipteris to fronds possessing this character irrespective of the entire or lobed form of the ultimate segments. He found among the numerous examples of the genus obtained from Autun[1500] and Lodève[1501] transitional forms connecting such species as C. conferta ([fig. 367]) and C. Pellati Zeill. ([fig. 366], C) in which the Pecopteroid pinnules are slightly lobed, with C. lyratifolia (Goepp.) ([fig. 366], D), C. flabellifera[1502] (Weiss), and C. Bergeroni Zeill. characterised by deeply lobed Sphenopteroid segments.

Callipteris conferta (Sternberg)[1503]. Fig. 367.

This polymorphic species ([fig. 367]) is one of the most characteristic Permian plants. The oval-linear pinnules, attached by the whole base, occur on both pinnae and rachis; this feature, the thick texture of the lamina, and the linear, obliquely set, pinnae render the fronds easily recognisable. The fronds bore seeds.

Fig. 367. Callipteris conferta. From the Permian of Aschbach, Rhenish Prussia (British Museum, No. 39052).

In a recent account of some Permian plants from Germany, Schuster[1504] refers a portion of a frond to Callipteris conferta (Sternberg) var. polymorpha Sterzel, which is characterised by unusually large and polymorphic pinnules. In size and shape the pinnules recall those of Neuropteridium validum Feist.