AFFINITIES OF LYGINODENDREAE 423 



Renault under the name of Gnetopsis elliptica} from 

 the Permo-Carboniferous of St. Etienne. In this case 

 four seeds (of which two are often abortive) are enclosed 

 within a common envelope or cupule, consisting of two 

 partly fused bracts, each of which is divided into about 

 five teeth above, and traversed by the same number of 

 vascular bundles. The seeds or ovules are small (2.5 

 mm. long) and have a remarkable structure. The 

 integument, which is traversed by four vascular strands, 

 expands around the micropyle into a chambered or 

 lacunar region, comparable to the canopy of Lagenostoma, 

 and bears two long feathery appendages. M. Renault 

 ingeniously suggested that the seed was thus adapted 

 to transport either by water or wind. The pollen- 

 chamber appears to have a central column as in 

 Lagenostoma, while the neck of the chamber is divided 

 into lobes. The endosperm and the two archegonia are 

 preserved. In several points — the structure of the 

 pollen-chamber and integument and the presence of a 

 cupule — there are thus decided analogies with the seed 

 of Lyginodendron, though the differences are no less 

 marked. An affinity with the Lyginodendreae certainly 

 seems more probable, in the present state of our 

 knowledge, than that with the Gnetaceae, originally 

 suggested by the discoverer. 



Our knowledge of the Lyginodendreae is far too 

 fragmentary at present for it to be possible to frame 

 the essential character of the family. The following 

 points may be mentioned as likely to occur in members 

 of the group : 



1 Cours de Bot.foss. t. iv. 1885, p. 179 ; Plate xx., Plate xxi. Figs. 1-6, 

 Plate xxi. Figs. 2-4. 



