928 MR A. C. SEWARD AND ME A. W. HILL ON THE 



cortex of Lycopodium inundatum (Linn.), and other species, and associated with the 

 foliar bundles of some Cycads.* It is possible that the secretory zone of Lepidophloios 

 had some share in the conduction of plastic organic substances, while the secretory tissue 

 of the phelloderm fulfilled a different purpose. 



The abundance of short and comparatively thin-walled tracheids is a question which 

 invites speculation as to the possibility of connecting certain anatomical characters with 

 the habit of growth of these Palaeozoic Lepidodendrese. Some at least of these elements 

 suggest a comparison with the transfusion tissue t of recent plants, to which reference 

 has already been made, and at the same time there is the possibility that in these short 

 tracheal cells we may have representatives of what have been called " Speicher- 

 tracheiden." j There are, indeed, indications in the anatomical features of the Dalmeny 

 Lepidophloios that the conditions of growth were such as to require the development of 

 characters usually associated with a xerophytic habit. The existence of striking xero- 

 phytic peculiarities in recent plants which inhabit seashore regions, as well as those of 

 arid regions, teaches the need of extreme caution in attempting to deduce from ana- 

 tomical data conclusions as to the environment of Palaeozoic species. On the whole, we 

 are disposed to see in the presence of xerophytic characteristics an indication that some 

 at least of the Carboniferous plants grew in seashore swamps under conditions which 

 necessitated the development of halophytic peculiarities. 



BIBLIOGRAPHY. 



Bertram), C. (91), "Remarques sur le Lepidoclendron Harcourtii de Witham," Travaux et .Memoires 

 des Faeulte de Lille, Mem. No. 6, Lille, 1891. 



Binney, E. W. (62), "On some Plants showing Structure from the Lower Coal-Measures of Lancashire," 

 Quart. Joum. Geol. Soc, vol. xviii. p. 106, 1862. 



(71), "Observations on the Structure of Fossil Plants found in the Carboniferoiis Strata. 



I't. II. Lepidostrobus and some allied Cones," Paltvont. Soc, London, 1871. 



(72), Ibid. Pt. III. Lepidodendron, 1872. 



Bower, F. 0. (93), "On the Structure of the Axis of Lepidostrobus Brownii, Schmp.," Annals Bot., 

 vol. vii. p. 329, 1893. 



Brongniart, A. (37), "Histoire des Vegetaux Fossiles," vol. ii., Paris, 1837. 



(39), " Observations sur la structure interieure du Sigillaria elegans," Areli. Mus. d'h/ist. Nat., 



vol. i. p. 405, 1839. 



Carruthers, W. (69), " On the Structure of the Stems of the Arborescent Lycopodiacese of the Coal- 

 Measures," Monthly Mi'-r. Joum., p. 177, 1869. 



(69), " On the Plant Remains from the Brazilian Coal-Bec^s, with remarks on the Genus 



Klemingites," Geol. Mag., vol. vi. p. 5, 1869. 



Corda, A. J. (45), "Beitrage Zur. Flora der Vorwelt," Prag., 1845. 



Plot, L. (93), "Rechcrches sur la zone pcrimudullaire de la tige," Ann. Hei. Nat. [7], vol. xxviii. p. 37. 



* <Jf. WoRSDELL (9G). 



t Vide WORSDELL (97), Zimmermann (80), etc. Short tracheids, similar to those of Lepidophloios, accompanying 

 the petiolar bundles have recently been described by Scott in Medullosa anylica. An excellent example of transfusion 

 tissue in a fossil conifer ban been figured by Solms-Laubach in Ullmannia [Solms-Laubach (84), pi. hi.]. 



| Eaberlandt (96), p. 354. [In a new genus recently described under the name Megaloxylon, the abundance of 

 large short tracheids, which probably served as reservoirs of water, is a characteristic feature. [Vide Seward (99).] 



