328 Scientific Proceedings, Royal Dublin Society. 



that identifications have been hitherto, of necessity, based on the macroscopic 

 characters — on the shape, mode of segmentation, and type of venation ; with 

 the exception of an observation by Saporta and Marion, nothing hitherto has 

 been revealed of the character of the epidermis. We propose to review the 

 affinities suggested by previous observers in the light of our observations. 



Hellehorns Affinities. 



Saporta and Marion base their rejection of Debey's reference of Deicalq^iea 

 to AraUophi/llum , and their own leference of it to the Helleboieae, mainly 

 on the peculiar mode of segmentation of the leaf indicated by the term 

 pedalo-digitate. The Bcwalquea likeness- is best indicated in Hellehorns 

 foetidus, as monographed by V. Schiffner (7). Its leaf is always distinctly 

 pedately divided, and consists of 7-10 small, lanceolate, finely sharp-toothed 

 leaflets. We have failed to note the agreement of the venation of Bncalquca 

 with that of Hellebore, observed by Saporta and Marion, who were not so 

 fortunate as ourselves in the state of preservation of their specimens, judging 

 from the remark of Hosius and von Marck that the Westphalian material 

 showed poorly preserved secondary veins. We give actual photographic 

 illustrations of the magnified venation of D. j'raxinifolia (PI. XII, fig. 3). The 

 secondary veins in Hellebore arise at a very acute angle from the midrib, send 

 off' branches right and left, and end like their outer branches in the teeth of 

 the leaflet. Each secondary vein is craspedodrome. In Beicalquca the 

 secondary veins come off at an angle of 60''-70°, and on nearing the margin 

 bifurcate to join by their forks with adjoining secondaries, which then form 

 a marginal network. They are thus camptodrome. A detailed comparison 

 of the venation does not support the Hellebore affinities of Dcwalquea. 

 Saporta and Marion describe the epidermis of Deivcdquea as formed of rounded 

 polygonal cells, with probably sinuous walls like those in Helleborus, and, we 

 may add, in many other genera. 



Nestler gives a fully illustrated account of the structure of Helleborus. 

 Stomata, 45 x 33;u, occur scattered on the under epidermis only. The lateral 

 walls of the lower epidermis cells are sinuous. Unicellular hairs occur, as in 

 Ranunculaceae generally. The upper epidermis shows marked cuticular 

 striation. Peltate hairs are unknown in Hellebore or any other Eanunculaceus 

 plant. The geographical distribution is also of interest. The Lower Danube 

 is the " Eldorado " of Helleborus, which is exclusively Old World, while 

 Dewalquca is represented by many species in the New World, as well as by 

 several in Europe. It would, however, be dangerous to support conclusions 

 of affinities on present-day distribution, there being many cases in which 

 fossil fruits prove the former wider occurrence of a genus or family. The 



