200 SUMMARY OF CURRENT RESEARCHES RELATING TO 



description with numerous figures of the development of the sexual 

 generation, antheridia, archegonia, embryo, sporophyte, its petioles, 

 stomata, vascular bundles, mucilage, protoxylem, stelar structure. The 

 author comes to the conclusion that in the few tree-ferns examined the 

 form of the stele is too directly adaptive to prove relationship. The 

 function of the stem decides the form of the stele. In a creeping stem, 

 not too bulky, a tubular stele is found, as in some species of Pteris, 

 Hypolepis, Polypodium punctatum, etc. In a creeping stem extensively 

 used for storage of starch and water an extreme polystely is found. In 

 an upright stem with crowded leaves a tubular stele with leaf-gaps 

 occurs, as in the tree-ferns and in large forms of Polypodium pennigerum 

 and Aspidium aculeatum. 



Submersed Fern.* — A. Ernst writes on the ecology and morphology 

 of Polypodium pteropus BL, a fern found growing submersed in a garden 

 tank in one of the Sunda Islands. There is no question that it is 

 P. pier opus, though differing somewhat from the normal land-form. 

 Its rhizome is much more developed and ramified, and produces adventive 

 rhizoids and organs of attachment ; the leaves are smaller and simple ; 

 scales fewer ; tissue less developed ; spore production is normal. On 

 the whole the differences are by no means so great as might have been 

 expected in a form with so different a habitat. 



Inconspicuousness of Ophioglossum vulgatum.f — Gr. Chauveaud 

 publishes a note on the frequent occurrence of Ophioglossum vulgatum 

 in the meadows of Charente, and shows how difficult the plant is to 

 discover, even when known to occur in the immediate neighbourhood. 

 He himself was unaware of the presence of the plant until, in making 

 •a gravel path, he destroyed the turf alongside. To his surprise this 

 bare strip produced a large crop of Ophioglossum in the following 

 spring. And a very careful search of the surrounding meadows 

 snowed that the plant was abundant, but remarkably inconspicuous. 

 The fertile spike is usually devoured by snails and slugs. 



Lycopodium alpinum in Dublin. J — W. B. Bruce records the finding 

 of Lycopodium alpinum on the summit of Cruagh, in Co. Dublin, at 

 1714 ft. above sea-level. Growing among short heather, it is difficult 

 to distinguish. D. Orr's previous record for the county has been 

 regarded as very doubtful. 



North American Ferns. — W. N. Clute§ publishes an article on 

 fifteen years of fern study, the period covered by the Fern Bulletin, in 

 which he calls attention to the paucity of fern literature in North 

 America in 1892, and traces the gradual development of the study in 

 succeeding years. E. T. Winslow || offers an interpretation as to why, 

 in Polystichum acrostichoides var. incisum, the much enlarged and 

 pinnately incised lower pinna? should be fertile at their tips. W. N". 

 Clute IT writes on the ecology of some tropical ferns, basing his account 



* Ann. Jard. Bot. Buitenzorg, xxii. (1908) pp. 103-43 (3 pis.). 



t Bull. Soc. Bot. France, lv. (1908) pp. 627-8. 



J Irish Naturalist, xvi. (1907) p. 368. 



§ Fern Bulletin, xv. (1907) pp. 97-100. 



|| Tom. cit., p. 101 (fig.). f Tom. cit., pp. 102-19. 



