194 KIDSTOX: TIIK FLORA OF TlIK CAHIJONIFKKOUS PERIOD. 



Linopteris Presl. {Dicfi/opti'rif! Gutbier not Lamoui'oux) tliuugli 

 rare in Britain, must not be omitted. In the form of the frond 

 and pinnules it is similar to Xearopteris, and specimens not 

 showing the nervation might easily be overlooked as belonging 

 to that genu.s, but it is at once distinguished by the nervation, 

 the veinlets of which unite among themselves to form a net-like reti- 

 culation (Plate XXX., fig. 2. Linopteris obliqua Bunbury sp. x 3;\). 



Though this genus is certainly not common in Britain, it 

 may be more common than supposed through being passed over 

 for Neuropteris. 



PECOPTERIDEiE. 



This family holds an important place among pakeozoic ferns. 

 Pecopteris Brongt. is the chief genus and contains many large 

 and fine species. It is chiefly represented in tlie Upper Coal 

 Measures, and Pecopteris arhorescens may be regarded as the 

 type (Plate XXVII., fig. 3). 



The pinnules in Pecopteris are attached to the rachis by 

 the whole of their base. They have straight sides and rounded 

 apices. The pinnules are sometimes united among themselves 

 at the base and possess a strong central mid-rib, from which — 

 according to the species — are given off simple or dichotomously 

 divided veins which extend to the margin. 



The fructification of many of these ferns consists of four 

 or five exannulate sporangia arranged in a stellate group, from 

 which circumstance the genus Asterotheca has been proposed for 

 them, though not generally adopted (Plate XXVII.. fig. 4). 



In the Middle Coal Measures, Peco^iteris [Asterotheca) is 

 represented l)y few species, but Pecopteris (Asterotheca) Miltoni 

 is fairly plentiful. Though this species also occurs in the Upper 

 Coal Measures, it is there associated with many other Pecopterids 

 which are not found below that horizon. 



The fronds of Pecopteris were of very large size and most 

 jjrobably some of the tree fern stems were the trunks of Pecopteris. 



The Pec. plAcmosa Artis sp. ( = Pec. dentata Brongt. Plate 

 XXVII., fig. 1, Plate XXXI., figs. 1-4), so common in the 

 Middle and Upper Coal Measures, forms the type of the genus 



