158 Mr Newell Arber, The seed-bearing habit 



The seed-bearing habit in the Lyginodendrece. By E. A. 

 Newell Arber, M.A., Trinity College, University Demonstrator 

 in Paleobotany. 



[Received 15 May 1905.] 



Among fossil plant remains, specimens showing two organs, 

 still in continuity with one another, are as a rule very rare. 

 Thus in the case of Lyginodendron, one of the most fern-like of 

 all the Upper Palaeozoic plants, while the seed, Lagenostoma* , and 

 other organs are now known in great detail, there has been no 

 evidence, so far, as to the manner in which the seeds were borne. 

 A new species Lagenostoma Sinclairi Kidston M.S. has, however, 

 been recently discovered, which throws light on this problem. 

 I am indebted to my friend Mr Kidston for permission to describe 

 this new and interesting seed. 



The morphology of Lagenostoma Sinclairi j- agrees very closely 

 with that of L. Lomaxi, which has been shown by Prof. Oliver 

 and Dr Scott \ to belong to Lyginodendron. As in the case of 

 L. Lomaxi, these seeds are enclosed in protective organs which 

 have been termed ' cupules ' ; the ' cupule ' of the new species 

 differing only in details from that of the seed previously described. 

 The special interest of the new specimens lies in the fact that, 

 in many instances, the seeds, enclosed in their cupules, are still 

 attached to the axes on which they were borne in the living state. 

 These axes are highly compound structures, the seeds apparently 

 terminating the finer branches. The type of branching is ex- 

 tremely irregular, and no pinnules of the ordinary foliar type are 

 borne on the seed-bearing axes. The highly compound nature 

 of these axes, the irregularity of the branching, and the fact that 

 the seeds terminate both the shorter and longer axes, indicate 

 that the morphology of the branched system is that of a compound 

 frond with reduced lamina. This conclusion is confirmed by the 

 close agreement between this seed and Lagenostoma Lomaxi, the 

 latter being now known to belong to a plant possessing highly 

 compound foliage of the Sphenopteris type. 



At the close of 1904, when the examination of these specimens 

 had been completed, only one case was known in which the seed- 

 bearing habit had been ascertained among the group Pterido- 

 spermese, to which these Fern-like spermaphytes are now assigned. 



* Oliver and Scott, Phil. Trans. R. Soc, Ser. B, Vol. 197, p. 193, 1904. 



f A full account of the morphology of this seed, and of another new species, will 

 shortly appear in the Proc. R. Soc. An abstract of this paper was published in the 

 Annals of Botany, Vol. xix., p. 326, 1905. 



J Oliver and Scott, ibid. 



