THE FOSSIL FLORA OF THE YORKSHIRE COAL FIELD. 205 



have been previously united with one or other of the species I regard as synonymous 

 with the Yorkshire plant : — 



Dactylotheca, Zeiller, 1883. 



1883. Dactylotheca, Zeiller. Ann. cl. Scienc. Nat., 6 e . ser., 'Bot.', vol. xvi. pp. 184 and 207, pi. ix. figs. 



12-15. 

 1888. Dactylotheca, Zeiller. Flore foss. Bassin houil. d. Valenciennes, p. 30, fig. 16. 

 1891. Dactylotheca, Kidston. Trans. Geol. Soc. Glasgow, vol. ix. p. 27, pi. ii. fig. 26. 

 1877. Senftenbergia, Stur. (not Corda) (in part), Culm Flora, vol. ii. p. 187. 

 1883. Senftenbergia, Stur. (not Corda) (in part), Zur. Morph. u. Syst. d. Culm u. Carbonfame, p. 33 (in 



Sitzb. d. It. Akad. d. Wissensch., vol. lxxxviii. Heft i. p. 665). 



Generic description. — Sporangia exannulate, oval or oval acute, formed of elongated 

 thick-walled cells, and attached to the secondary veins a little above their point of 

 origin. 



Remarks. — The first description of the fruit of Pecopteris dentata, Brongt. 

 ( = Pec. plwnosa, Artis, sp.), is that given by Zeiller in 1880,* but he did not till 

 1883 create the genus Dactylotheca for the reception of this species. 



In 1877 Stur included Pecopteris dentata in the genus Senftenbergia, Corda,t but 

 this is clearly an error, for the chief characteristic of the genus Senftenbergia is the 

 presence of a very prominent apical annulus, whereas the sporangia of Dactylotheca are 

 absolutely devoid of any annulus, even in its most rudimentary form. 



Mons. Zeiller has detected a longitudinal band of narrower cells in the direction in 

 which the sporangia appear to have opened at maturity. This longitudinal band I have 

 not observed on my specimens, but it can only be seen in one position of the sporangia. 



Dactylotheca is Marattaceous, and amongst recent ferns finds its nearest ally in 

 Angiopteris. 



Dactylotheca plumosa, Artis, sp. 

 Pis. I.-III. 



1886. Dactylotheca plumosa, Kidston. Catal. Palseoz. Plants, p. 128. 

 1890. „ „ ,, Trans. York. Nat. Union, part xiv. p. 36. 



1825. Filiates plumosus, Artis. Antedil. Phytol., p. 17, pi. xvii. 

 1.-28. Pecopteris plumosa, Brongt. Prodrome, p. 58. 

 ^$6.. „ „ „ Hist. d. veget. foss., p. 348, pis. cxxi.-cxxii. 



1869. ,, ,, Roehl. Foss. Flora d. Steink. Form. Westph., p. 88, pi. xxvii. fig. 4. 



1877. Senftenbergia plumosa, Stur. Culm Flora, Heft ii. p. 187 (293). 

 1883. ,, „ „ Morph. u. Syst. cl. Culm u. Carbonfame, p. 44. % 



1885. ,, „ ,, Carbon-Flora, I. Fame cl. Carbon-Flora d. Schatzlarer Schichten., 



p. 92, pi. Ii. figs. 1-3. 

 1828. Pecopteris dentata, Brongt. Prodrome, p. 58. 



* Ve'get. foss. du terr. houil., p. 87. 



t Corda, Beitr. z. Flora cl. Vorwelt., p. 91, pi. lvii. figs. 1-6, 1867. 



% Sitzb. d. k. z. Akad. d. Wissensch., vol. lxxxviii. Abth. i. p. 633, 



