1903.] On Lagenostoma Lomaxi, the Seed 0/ Lyginodendron. 477 



" On Lagenostoma Lomaxi, the Seed of Lyginodendronr By 

 F. W. Oliver, D.Sc., F.L.S., and D. H. Scott, MA., Ph.D., 

 F.RS. Eeceived March 19,— Bead May 7, 1903. 



The existence in Palaeozoic times of a gronp of plants (the Cycado- 

 filices of Potonie) combining certain characters of Ferns and Gymno- 

 sperms, has been recognised for some years past by various palseo- 

 botanists.* The group in question embraces a number of genera, 

 among which Medullosa, Heterangium, Calamopitys and Lyginodendron 

 may be mentioned ; the fern-like foliage of these plants is placed 

 according to its external characters in the form-genera Aletlwpteris, 

 Neuropteris, Sphenopteris, and others. 



The evidence for the intermediate position of the Cycadofilices is 

 extremely strong, but at present it is drawn entirely from a detailed 

 comparison of their vegetative organs, especially as regards their 

 anatomical characters. In no case, as yet, is the fructification of any 

 member of the group known with certainty ; such indications as have 

 hitherto been detected are still in need of corroboration. Thus, the 

 suggestion has been made that the large seed, Trigonocarpon olivceforme, 

 may have belonged to some member of the genus Medidlosa ;f and in 

 the case of Lyginodendron itself there is fairly strong reason to believe 

 that one form of fructification (in the light of the observations to be 

 described below, presumably the male) may have been of the Calym- 

 matotheca type,! a type, however, of which the organisation is not yet 

 fully understood. In the absence of satisfactory data as to the fructi- 

 fication, so high an authority as M. Zeiller has expressed a doubt 

 whether the Cycadofilices were, after all, anything more than a 

 specialised group of Ferns. § 



A re-examination of the seeds, placed by Williamson in his genus 

 Lagenostoma, has revealed unexpected points of agreement between the 

 structure of the envelopes of certain of these seeds, on the one hand, 

 and that of the vegetative organs of Lyginodendron on the other. 



Two species of Lagenostoma (L. ovoides and L. physoides) were 



* Williamson, "Organisation of the Fossil Plants of the Coal-measures, Part 

 XIII," 'Phil. Trans.,' B, vol. 178, p. 299;. 1887; Solms-Lauhach, 'Fossil Botany,' 

 1887, Engl, ed., pp. 141 and 163; Williamson and Scott, "Further Observations on 

 the Organisation of the Fossil Plants of the Coal-measures, Part III," 'Phil. 

 Trans.,' B, vol. 186, p. 769, 1895 ; Potonie, ' Lehrbuch der Pflanzenpalseontologie,' 

 p. 160, 1899 ; Scott, ' Studies in Fossil Botany,' pp. 307 and 514, 1900. 



f G-. Wild, " On Trigonocarpon olivceforme" ' Manchester Greol. Soc. Trans.,' 

 vol. 26, p. 434, 1900. 



% Scott, 'Studies' p. 334; Mi*s Benson, "The Fructification of Lyginodendron 

 Oldhamuim," 'Ann. of Bot.,' vol. 16, p. 575, 1902. 



§ ' Zeiller, 1 Elements de Paleobotanique,' 1900, p. 370. 



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