108 PROF. A. C. SEWARD ; CONTRIBUTION TO [March 1913, 



Notes on the List of British Wealden Plants. 



Chara hnowltoni Sew. — Fragments of Chara preserved in the 

 Purbeck chert-beds, near Swanage, have also been referred to this 

 species. 1 



Tempslcya schimperi Corda. — This species, with two others, is 

 included provisionally in the family Schizseacese, on evidence which 

 cannot be regarded as conclusive. In a recent account of a Eussian 

 species of Tempslcya Dr. Kidston & Prof. Gwynne-Vaughan 2 corr? 

 tribute important information with regard to the anatomy of 

 the stem and petiole, and discuss the affinities of the genus. The 

 presence of a solenostele in the stem, as the authors point out, 

 while suggesting a comparison with certain recent Schizseaceee, as 

 with some. other ferns, is not in itself a conclusive criterion as to 

 systematic position ; but the discovery by Mr. Boodle 3 of ridged 

 spores embedded in the tissues of the Wealden species is noted 

 as a point in favour of, though not demonstrating, relationship to 

 the Schizaeacea?. 



Dicliopteris. — The position of this genus is still undecided, and, 

 though included in the above list in the Filicales, it has not been 

 proved a fern. 



Weicliselia mantelli (Brongn.). 4 — Dr. Bommer 3 has recently 

 published an interesting preliminary note on this characteristic 

 Wealden plant, in which he describes some imperfectly-preserved 

 reproductive organs, originally described from isolated specimens 

 as Conites minutus ° ; he also throws fresh light on the morphology 

 of the frond, and shows that the specimens hitherto regarded as 

 portions of bipinnate fronds are large compound pinnae borne in a 

 fan-like cluster at the expanded summit of a thick petiole, the 

 anatomy of Avhich is described. Dr. Bommer compares WeicJiselia 

 with the Matoninese and Marattiacece, suggesting also the possibility 

 of a Pteridosperm alliance. 



Dioonites dunlcerianus (Gcepp.). — Prof. N~athorst 7 draws attention 

 to a certain resemblance between the epidermal structure of this 

 species and that of Psendocycas insignis Nath., without suggesting 

 specific or even generic identity. 



Elatides. — It should be pointed out that the reference of this 

 genus to the Araucarinese is based on the structure of some cones, 8 

 and not only on a similarity in habit of vegetative shoots. The 

 Araucarian affinity, although very probable, cannot be regarded as 

 definitely established. 



1 Seward (98) p. 224, fig. 45, A & B. 



2 Kidston & Gwynne-Vaughan (11). 3 Boodle (95). 



4 = Weicliselia reticulata (Stokes & Webb). 3 Bommer (10). 



e Seward (00) p. 28 & pi. iv, figs. 60-62, 64. r Nathorst (07 2 ) p. 6. 



* Seward (11) p. 685; Nathorst (97) p. 58. 



