ee ee a eS ee eee 
BOOK-NOTES, NEWS, ETC. 191 
eee varieties on the salt marsh. Evidence is boruahs forward 
to show that these forms, although they differ widely in their 
morphology from their roc ancestors, are to be regarded as 
adaptational varieties or ‘‘ ecads,” in the terminology of Clements. 
Fucus vesiculosus L. forms a long series of ecads whose diversity 
has caused some confusion in the nomenclature; they have 
m 
F. lutarius Kitz., F. balticus Ag., F. subecostatus Ag., or as 
varieties of F’. vesiculosus (var. eid Cott. and var. spiralis 
Farlow). These forms are parallel to but not identical with the 
series of forms, also derived from F. vestculosus, found in the 
; isc—a n 
marsh forms of all the species. nde this megecad of F’, vesicu- 
losus it is. Sew: to use the three ecads e. volubilis Huds., 
e. cespitosus, and e. muscotdes Cott., the name F’. balticus Ag. 
pie rejected as liable to cause confusion. A new marsh form is 
ribed, derived from fF’. ceranoides L. Morphology: Two 
the second to examine in detail exceptional cases. These methods 
have led to the conclusions that dwarf habit is mainly conditioned 
by exposure and lack of nutrient salts. Vegetative reproduction 
is caused by the high humidity ind ee over the marsh in the 
intertidal periods. This prevents the attainment Zs a limiting 
concentration in the cell-sap necessary as a stimulus to the 
formation of sexual reproductive organs. The cause of svar 
is probably unequal distribution of nutrient salts. The sa 
‘factors were shown to be operative in ge the pene a 
morphology of the floating Sargasso weed. ogy: Brown sea- 
eeds may function on salt marshes either as ‘pionger ee 
sad growth, or covering vegetation after erosion, and 1 ese 
ities number (vol. iv. No. 4) of the Journal of Genetics — 
on April ae contains several papers of botanical interest 
Rk. P. Gre has a note on the inheritance of heter rostylism in 
Primula anki and a Bn al om be plates) on variegation in 
£. Aeteatet writ ary and seconda 
of Mr. G. H. Sh nblished in the Journal of Genetics for 1914) 
on his conclusions as to the Cpe and behaviour of (nothera 
rubra rizes recent chemical ie 
ZL; . Eve 
vestigations of the atlicavan teases and their bearing u 
