SPHENOPHYLL ALES— THE GENUS SPBENOPHYLLUM. 173 



EADICITES PALMATIFIDA. (Lx.). 



1860. RMzolitlies palmatifidus Lesquereux, Kept. Geol. Surv. Arkansas, vol. ii, p. 313, 

 pi. V, fig. 9. 



1879. MMzolithes palmatifidus Les<iuereux, Coal Flora, Atlas, p. 16, pi. Ixxv, fig. 9; 



text, vol. 1 (1880), p. 518. 



1880. Pinnularia palmatifida Lesquereux, Coal Flora, vol. i, p. 518. 

 1889. Pinmdaria palmatifida Lx., Miller, Geol. Pal. N. Amer., p. 126. 



The specimens referred to this species are rather larger than that 

 originally illustrated from the coals of Arkansas. The rootlets are thin in 

 texture and apparently flaccid. The}^ are larger and more lax than those 

 referred to Radicites capillacea. 



Locality. — Owen's coal mine, U. S. Nat. Mus., 5587. 



SPHENOPHYLLALES. 



SPHEISrOPHYLLE.E. 



SPHENOPHYLLUM Brongniart, 1828. 



1822. SphamophylUtes Brongniart, Mem. mus. hist, nat., vol. viii, p. 209. 



1822. 8pheno])hyllites Brongniart, Mem. mus. hist, nat., vol. viii, p. 234. 



1823. Rotularia Sternberg, Versuch, vol. i, fasc. 2, p. 33 : tent, 1825, p. xxxii. 

 1828. Splienophyllum Brongniart, Prodrome, p. 65. 



Fructification. 



1871. Boiomanites Binney, Obs. Struct. Foss. PI. Carb. Str., pt. ii, p. 59. 

 1898. Sphenopliyllostachys Seward, Foss. PL, vol. i, p. 402. 



The systematic affinities of the genus Sphenophyllum are now some- 

 what definitely known through the study of the anatomical characters of 

 the various organs of the plant. Most important among the recent correla- 

 tions is the recognition on the part of Professor Zeiller of Boivmcmnites, so 

 thoroughly analyzed by the late Professor Williamson, as the fruiting spike 

 of Splienophyllum. In Bowmannites Daivsoni (Will.) Zeiller found the details 

 obscurely revealed to him in his study of the S. cuneifolmm (Stb.) Zeill., 

 from the Valenciennes Basin, to which I have previously made reference.^ 

 As now demonstrated,^ the ovoid or oval sporangia are pluriseriate in each 



' Bull. V. S. Geol. Surv., No. 98, p. 39. 



- R. Zeiller, Sur la coustitution des episde fructification du Splienophyllum cuneifolium: Comp- 

 tes Rendus, vol. cxv, 1892, pp. 141-144. fitude sur la constitution de I'appareil fructificateur des 

 Splienophyllum: M^m. Soc. G^ol. Fr., Pal<Sont., vol. iv, m^m. 11, 1893, pp. 1-39, pis. i-iil. 



