RADSTOCK SERIES OF THE SOMERSET AND BRISTOL COAL FIELD. 383 



plumosa the Pec. pennceformis, Brongt, a species which, when the authentic 

 plant is seen, is specifically distinguishable by many well-marked characters. 



In my Catalogue of Palaeozoic Plants I united Pec. acuta, Brongt., with 

 Dactylotheca plumosa (including var. dentata), Artis, sp. I have since had a 

 specimen of Pec. acuta, Brongt., from Prof. Weiss, and now find my uniting 

 them was an error. The uniformly simple nervation of Pec. acuta, as well 

 as the acute falcate form of its pinnules, easily separate it from Dacty. plumosa, 

 var. dentata. These differences are, however, better seen on actual specimens 

 than in Brongniart's figure. 



Aspidites Glockeri, Gopp.,* was also regarded by me as a variety of Dacty. 

 plumosa, Artis, sp., but perhaps it is not safe positively to refer Goppert's 

 plant to Artis's species without a comparison of specimens. 



The fruit of Dacty. plumosa, var. dentata, has been described by ZEiLLER.t 

 It consists of broadly-lanceolate marattiaceous exannulate sporangia situated 

 on the arms of the secondary nerves. The sporangia are not united to one 

 another, and appear to open by a longitudinal cleft. 



From characters derived from the structure of this fruit, Zeiller has founded 

 the genus Dactylotheca for Pecopteris dentata, Brongt,, which is adopted here. 



Dactylotheca plumosa, Artis, sp.. 

 Locality : — Upper Conygre Pit. 



Dacty. plumosa, var. dentata, Brongt., sp. 



Localities: — Radstock; Braysdown Colliery; Wellsway Pit; Upper Conygre 

 Pit ; Lower Conygre Pit ; Camerton. 



Dicksoniites, Sterzel, Botanisches Centralblatt, Band xiii. 



Nos. 8, 9, 1883. 



Dicksoniites Pluckenetii, Schlotheim, sp. 



Dicksoniites Pluckenetii, Sterzel, Botan. Centralblatt, Band xiii. Nos. 8, 9, pi. vi. ; Zeitsch. d. deut. 



geol. Gesell., 1886, p. 773, pi. xxi. 

 Pecopteris Pluckenetii, Brongt., Hist. d. veget. foss., p. 355, pi. cvii. figs. 1-3. 

 Pecopteris Pluckenetii, Germar, Vers. d. Steinkf. v. Wettin u. Lobejun, p. 41, pi. xvi. 

 Pecopteris Pluckenetii, Zeiller, Veget. foss. d. terr. houil., p. 90, pi. clxviii. figs. 1, 2. 

 Alethopteris Pluckenetii, Geinitz, Vers. d. Steinkf. in Sachsen, p. 30, pi. xxxiii. figs. 4, 5. 

 Cyatheites Pluckenetii, Weiss, Foss. Flora d. jiiiigst. Stk. u. d. Rothl., p. 67. 

 Filicites Pluckenetii, Schlotheim, Flora d. Vorivelt, p. 52, pi. x. fig. 19. 

 Pecopteris bifurcata, Sternb., Vers., i. p. xix. pi. lix. fig. 2 ; ii. p. 151. 



Remarks. — Though this species has been noted from several localities, it is by 

 no means common. All the examples collected are referable to the typical form. 



* Syst. fil. foss., p. 375, pi. xxix. figs. 1-4. 



f Ann. d. sc. not. Bot., 6 e s£r., vol. xvi. p. 184, pi. ix. figs. 12-15. 



VOL. XXXIII. PART II. 3 L 



