Botany. 241 



the surface of the sporangia, appearing to form a disc which pre- 

 sumably assists in the dehiscence of the microspores found within, 

 the arrangement of the parts being apparently analogous to those 

 of the Eusporangiate ferns. The number of concentric rows of 

 sporangia to each internode varies with the species. In one sec- 

 tion two pedicels in the row to one bract were observed. It is not 

 known how the vascular bundle, which seems to be slightly 

 developed in the pedicel, reaches the axis of the cone, nor whether 

 the pedicels branch, though it is thought that in one species at 

 least they do so. 



After describing in detail the cones of 8. cuneifoliwn M. Zeiller 

 reviews what is known of the fructification of S. emarginatum, S. 

 gracile, and 8. oblong if olium on all of which he records new obser- 

 vations. A re-examination of the cone described by Renault 

 (Cours de bot. foss., II, pp. 102, 103), which has considerably 

 influenced opinion as to the relations of the genus, brings both 

 Renault and Zeiller to the conclusion that only one kind of spo- 

 rangia was present, instead of both macrosporangia and micro- 

 sporangia as was at first supposed. 



Also Zeiller and Williamson agree that the leaves of Spheno- 

 phyllum are sometimes dissected to the base so as to resemble 

 Asterophyllites, a circumstance that led the latter to refer JBoio- 

 manites Dawsoni to Asterophyllites, and which, together per- 

 haps in some instances with vertical burial of the leaves in the 

 matrix, caused Director Stur to maintain that 8p>henophyllum 

 is the heteromorphous, heterosporous branch of Catamites, while 

 Asterophyllites is the homomorphous branch, a view somewhat 

 modified by Seward (" Sphenophyllum as a bi*anch of Asterophyl- 

 lites," Mem. Proc. Manchester Lit. Phil. Soc, 1890). 



As to the systematic position of the genus, Williamson in his 

 short note in "Nature" agrees with Zeiller that while the organi- 

 zation of the stem allies it to the Lycopodineae, its highly special- 

 ized fructification brings it nearer the Rhizocarpeaa, and that it 

 forms a distinct class among the Vascular Cryptogams. Kidston, 

 in a recent paper " On the Fructification of Sphenophyllum 

 trichomatosum, Stur, from the Yorkshire Coal Field " (Proc. R. 

 Phys. Soc. Edinb., xi, pp. 56-62, PI. I), reaches the conclusion 

 that there is no recent order in which the genus can be enrolled, 

 since it differs from the Equisetaceae by its solid axis and the 

 structure of its cone, from the Lycopods by its ribbed, noded 

 stems with verticillate leaves, while " with the Rhizocarps it ap- 

 pears to have little or nothing in common." He therefore makes 

 the Sphenophylla a peculiar aud distinct group, the Sphenophyl- 

 lece, which though close to the Lycopods can not be included 

 with them. Finally, Zeiller, after considering its resemblance in 

 the development of a secondary or centrifugal growth to the 

 Lycopodinse the stronger analogy of its fruiting cones to the 

 Hydropterideae and Ophioglossaceae, its several "characters in 

 common with the Equisetinese, agrees essentially with the others 

 in constituting for it a distinct class in the Vascular Cryptogams, 



Am. Jour. Sci.— Third Series, Vol. XLVII, No. 279.— March, 1894. 

 16 



