THE ORIGIN OF GYMNOSPERMS 227 



fossil plants of Palaeozoic age. It was chiefly, but not entirely, 

 on the identity of these glands, that Prof. Oliver and Dr. Scott 

 were able to refer Lagenostoma Lomaxi to Lyginodendron. 



Although the seed-bearing habit in this particular instance 

 is as yet unknown, in the case of another Lagenostoma {L. Sin- 

 clairi), described more recently, 1 the seeds, also enclosed in 

 cupules, have been found attached to a highly branched structure, 

 which is interpreted as a frond with reduced lamina. In fact, 

 in all the examples among these fern-like plants, in which the 

 seed-bearing habit has been ascertained, the seeds were borne 

 on fronds, either little modified and similar to the sterile 

 foliage, or on fronds with reduced blade or lamina. 2 Thus 

 these ancient seed-bearing, fern-like plants must have presented, 

 in the lax manner in which the fructification was borne, a 

 striking contrast to almost all the other great Palaeozoic groups 

 of plants, where the sporangia were aggregated into cones. If 

 we could see to-day a landscape as it was in Carboniferous times, 

 we should no doubt be struck by the diversity of cone-bearing 

 plants as compared with those in which the fructification was to 

 be found on the fronds, in much the same manner as sporangia 

 occur on the fronds of living ferns. Only here, in most cases, 

 but not in all, the sporangia were heterosporous, the female or 

 megasporangium being of that particular nature which we call 

 a seed. 



Since 1903, as we shall see, several other discoveries relating 

 to the nature of the female fructifications of members of the 

 Cycadofilices have followed rapidly on the heels of the initial 

 attribution of the seed Lagenostoma to Lyginodendron. We 

 may, however, before considering these, complete the story 

 so far as it relates to that genus. 



It is only quite recently that we have come to know any- 

 thing of the male organs of the Cycadofilices. Yet, curiously 

 enough, the first, and at present the only discovery in this 

 direction, also relates to this same plant Lyginodendron. 

 Mr. Kidston 3 showed last year (1905) that a particular form 

 of sporangial aggregation or sorus, borne on a frond in which 

 the blade or lamina was somewhat reduced and already well 

 known as a detached fossil under the name Crossot/icca, was 

 in reality the male fructification of Lyginodendron. He had 



1 Arber, 1905 1 ; Scott and Arber, 1905. 



2 Arber, 1905 2 . :! Kidston, 1905, 1906. 



