306 BOTANICAL GAZETTE [APRIL 
are given, comparing the littoral climate of Belgium with that on other European 
coasts. By-reason of mild temperatures, many plants retain green leaves through 
the winter, notably winter annuals, biennials, and many evergreen herbs. _ Other 
topics here treated are bud protection (RAUNKIAER’S classification being followed), 
fixation of dunes by vegetation (mosses and lichens being of great importance in 
this), reactions to the deposit and denudation of sand (e.g., ascent or descent of 
rhizomes), rigidity of the aerial organs, ‘‘adaptations” against desiccation. Con- 
sideration is next given to the soil, many analyses being presented, and to the 
influence of animals and of other plants upon the vegetation. Some attention is 
devoted to succession, as on the dunes, where Erodium often appears on a fresh - 
surface, giving way later to Festuca rubra, and this to Tortula, and this again to 
various herbs, the succession culminating in a stand of Salix repens. 
The third chapter has to do with the plant associations (the term. formation 
being discarded). An association is defined as “‘I’ensemble des espéces végétales 
qui sont adaptées aux mémes conditions d’existence et qui vivent donc en mélange 
dans une station, c’est-A-dire dans l’endroit o& ces conditions d’existence sont 
réalisées.” After considering the conditions obtaining on the littoral dunes, 
ssart takes up the detailed features of the mobile and fixed dunes, the dry and 
winter pools and permanent pools, cultivated lands and forest 
plantations. The marine and fluvial alluvia are next considered, attention being 
given to the tidal belts (slikke and schorre), ditches, mounds, polders, 
brackish and fresh waters, ponds, canals, dikes, and cultivated areas. Finally 
there are treated the plants of the Cardium sands 
A chapter is devoted to a floristic comparison between the littoral and alluvial 
districts and other neighboring districts, Belgium being regarded as divided into 
two main regions, the domain of the plains and the domain of the hills and moun- 
tains. The final chapter deals with the origin of the flora. In the region, con- 
sidered there is not a single endemic species. The dune flora is dominantly 
“calcicole,” thus differing from the dune floras of Holland, Denmark, and Get- 
Ae The Cardium sands, on the other hand, are tenanted mainly by “calcl- 
ges.” 
The Annexe is devoted in part to a detailed list of plants, with data arranged 
in columns showing distribution in Belgium and elsewhere in Europe, and also 
giving the characteristic vegetative features of the plants considered, a unique 
and most suggestive kind of tabulation. Most of the Annexe, howevet, is 
filled with photographic reproductions of the various habitats, diagrams, and 
maps. ‘The work on “Aspects de la végétation”’ (following out a plan elaborated 
by BomMer in 1903) presents the same or similar photographs in most sumptuous 
form, the plates having the unusual size of 30%40°™. Doubtless these at© 24 
most excellent ecological photographs that have ever been taken, and they are also 
issued in the most perfect form of any that have yet appeared. Indeed the entire 
monograph, including the detailed text with its many tables of climatic and edaphic 
data and vegetative features, as well as the numerous illustrations, may seTve - 
one of the best models now extant for future ecological workers. Many of our 
