Notes , 
625 
ON LAGENOSTOMA LOMAXI, THE SEED OF LYGINO- 
DENDRON h— ' The existence in Palaeozoic times of a group of 
plants (the Cycadofilices of Potonid) combining certain characters of 
Ferns and Gymnosperms, has been recognized for some years past 
by various palaeo-botanists 2 . The group in question embraces a 
number of genera, among which Medullosa , Heierangium, Calamopitys , 
and Lyginodendron may be mentioned ; the fern-like foliage of these 
plants is placed according to its external characters in the form-genera 
Alethopteris , Neuropteris , Sphenopleris, 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 olivae- 
forme , may have belonged to some member of the genus Medullosa 3 ; 
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 
Calymmatotheca type 4 , a type, however, of which the organization is 
not yet fully understood. In the absence of satisfactory data as to the 
fructification, so high an authority as M. Zeiller has expressed a doubt 
whether the Cycadofilices were, after all, anything more than a 
specialized group of Ferns 5 . 
A re-examination of the seeds, placed by Williamson in his genus 
Lagenosioma , 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. 
1 Read before the Royal Society on May 7, 1903 ; reprinted from the Proceedings. 
2 Williamson, Organization of the Fossil Plants of the Coal-measures, Pt. XIII, 
Phil. Trans., B, vol. clxxviii, p. 299, 1887; Solms-Laubach, Fossil Botany, 1887, 
Engl, ed., pp. 141, 163; Williamson and Scott, Further Observations on the 
Organization of the Fossil Plants of the Coal-measures, Pt. Ill, Phil. Trans., B, 
vol. clxxxvi, p. 769, 1895 ; Potonie, Lehrbuch der Pflanzenpalaeontologie, p. 160, 
1899; Scott, Studies in Fossil Botany, pp. 307, 514, 1900. 
3 G. Wild, On Trigonocarpon olivaeforme , Trans. Manchester Geol. Soc., vol. 
xxvi, 1900. 
1 Scott, Studies, p. 334 ; Miss Benson, The Fructification of Lyginodendron 
Oldkamium, Ann. of Bot., vol. xvi, p. 575, 1902. 
5 Zeiller, Elements de Paleobotanique, 1900, p. 370. 
