ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 241 



Brown Seaweeds of the Salt Marsh.* — Sarah M. Baker and Maude 

 H. Bohling have made an investigation of the brown seaweeds which 

 form a conspicuous feature of some salt marshes, of their relation to the 

 recognized systematic species, and of the effect of the physical conditions 

 of the marsh upon the morphology of the plants. Of the common 

 littoral Fucaceae it is the following species to which the marsh forms 

 are traced by the authors — Pelvetia canalicuJata, Fucus spiralis, F. vesi- 

 culosus, F. ceranoides, Ascophylhmi nodosum ; and to F. vesiculosus in 

 particular are ascribed six of the forms. These ecological forms have 

 been misunderstood by earlier writers or have been overlooked. They 

 are derived from the rock-fixed recognized plants either by direct 

 vegetative budding or by the modification of young plants germinating 

 upon a salt marsh. Each individual species undergoes a series of 

 striking morphological modifications in the transition from rock to salt 

 marsh, and the adaptational varieties so produced are termed " ecads," 

 and are persistent through many vegetative generations. The marsh 

 ecads of the above five species, being all of the same general type, are 

 grouped together under a " megecad limicola,^^ including all the marsh- 

 dwelling Fucoids as distinguished from those of saxicolous habit. The 

 characteristics of the megecad limicola are briefly : — 1. Vegetative 

 reproduction. 2. Dwarf habit. 3. Absence of attachment disk. 4. 

 Spirality or curling of the thallus. The methods of investigation 

 employed by the authors show that dwai-f habit is due to prolonged 

 exposure to the air and diminished immersion in the water ; that curling 

 or spirality is probably due to an unequal distribution of water and 

 nutrient salts upon the thallus as it lies spread out on the intertidal 

 mud ; that vegetative reproduction is probably favoured by the constant 

 humidity of the intertidal mud, thus preventing that concentration of 

 cell-sap which is essential as a stimulus for the production of receptacles 

 and for the maturing of sexual organs. The authors add that "an 

 examination of the famous floating Sargasso weed revealed the interesting 

 fact that its peculiarities could be referred to the same physical factors 

 as those of the marsh Fucoids — a confirmation of Borgesen's contention 

 that it is produced and reproduced vegetatively from one of the saxi- 

 colous Sargassums." 



Marine Alg-ae of the Island of Elba.f— G. B. de Toni publishes a 

 list of the marine algge recorded from the island of Elba, compiled 

 mainly from the collections made by the Countess Vittoria Toscanelli, 

 during the years between 1877 and 1882. The number of species 

 recorded is 114. The list of alga is preceded by the publication of the 

 letters written by the Countess to Professor Ardissone on the subject of 

 the algae she found. 



Algae of the Gulf of Spezia.J — A. Preda publishes the second 

 contribution to his algological flora of the Gulf of Spezia, the first part 

 of which appeared in "Malpighia," xviii. p. 76. The work was 



* Journ. Linn. Soc, xliii. (1916) pp. 325-80 (3 pis. and Sgs.). 

 t Nuov. Notar., xxxii. (1917) pp. 1-58. 

 X Nuov. Notar., xxxii. (1917) pp. 59-69. 



