636 SUMMARY OF CURRENT RESEARCHES RELATING TO 



certain modifications. It agrees fairly closely with other Laminariaceae 

 in its anatomy. Mucilage canals however do not occur, and no crypto- 

 stomata were seen. 



Pelvetia fastigiata.* — F. L. Holtz publishes observations on this 

 species, treating the various parts of the plant in detail. Both external 

 appearance and internal structure are fully described, and the develop- 

 ment of the conceptacle is treated at length. He disagrees with 

 F. 0. Bower in certain points connected with the early stages of the 

 development of the conceptacle, being of opinion that it originates from 

 several contiguous epidermal cells, and not from one central basal cell. 

 The stages of growth seen by the author are figured. The antheridia 

 arise sometimes on branched hairs, sometimes on simple pedicel-cells 

 from the wall of the conceptacle. The plant is hermaphrodite. Methods 

 of staining and sectioning are described. 



New Alaria.f — H. F. Schrader describes and figures a new species 

 of Alaria, A. nana, found by him at the Minnesota Seaside Station, 

 growing in very exposed situations and always beaten about by the surf. 

 The plant is small, 30-50 cm. long, the holdfast does not show any 

 growth-rings, and the growth of the stipe in thickness is radial. There 

 are neither mucilage-ducts nor cryptostomata. The sori are borne on 

 gonidiophylls which are produced laterally on the stipe. The paraphyses 

 have large, thick, mucilaginous caps as in Lessonia and Pterygopliora. 



Polymorphism of Marine Algae.:}: — F. Tobler has experimented on 

 six species of Floridere with regard to polymorphism, and publishes a 

 list of the various forms each species may assume under different con- 

 ditions. His experiments include growth in darkness and in light and 

 at different times of year. He was able to compare the results of his 

 artificial growth with the growth of algaa thrown up on the shore after 

 storms, since certain of such plants continued to grow, but in abnormal 

 manner. One result of his observations, which he considers among the 

 most important, is the dissolving of the connection between the different 

 cells of an alga, not as a forerunner of decay, but as an introduction to 

 active independent life on the part of the individual cells. He discusses 

 the question of polarity in connection with the growth of these isolated 

 cells, and touches on the subject of seasonal forms of one and the same 

 species. Further information on various points connected with this 

 subject is promised later. 



New Rhododermis.§ — F. Heydrich describes and figures a new 

 species of Rhododermis, R. Van Heurckii, which grows on young Zostera 

 leaves off the coast of Jersey. In its young stages the thallus shows 

 the characteristics of the genus, but in later stages the new species 

 varies in certain points. In some cases as soon as the first tetra- 

 sporangia have been emptied from that part of the plant which grows 

 over the sharp edge of the Zostera leaf, the thallus swells up and forms 

 irregular kidney-shaped outgrowths, which hang somewhat over the edge 

 of the host-plant. In other specimens the internal cells may vary in 



* Minnesota Bot. Studies, iii. (1903), pp. 23-45 (6 pis.). ' 

 t Tom. cit, pp. 157-65 (4 pis.). 



\ S.B. K. Preues. Akad. Wissensch., xviii.(1903) pp. 372-84. 

 § Beih. Bot. Centralbl., xiv. (1903) pp. 243-6 (1 pi.). 



