100 Floristik, Geographie, S3^stematik etc. 



The method is to trace from the works of different writers what 

 they mean, what their concept is when they use such terms as 

 association and formation. The abstracts from authors are numerous 

 and one can only refer here to the more important of the author's 

 interpretations. As regards the „plant association", it appears that 

 in spite of considerable divergence, the concept held by most 

 authors from Humboldt onwards has been that something less 

 than a plant formation, something which may be expressed as by 

 E. Warming (1909): „an association is a Community of definite 

 floristic composition within a formation." 



The „plant formation" is more difficult to grasp. Grisebach's 

 definition is somewhat obscure, but the author considers that there 

 is sufificient agreement between this and later writers to Warrant 

 the view that „a plant formation may be regarded as the Vegetation 

 co-existent with a definite habitat." To this may be added a general 

 acceptance that for each habitat there is a closed, ultimate or chief 

 association (after Drude), which is reached through a succession of 

 associations or phases of Vegetation. The author's expression of these 

 concepts may be quoted : „A plant formation comprises the progressive 

 associations which culminate in one or more stable or chief asso- 

 ciations, and the retrogressive associations which result from the 

 decay of the chief associations, so long as these changes occur on 

 the same habitat." This excludes a definition or concept based on 

 growth forms (Warming, 1909) or on a floristic foundation (Brock- 

 mann-Jerosch, 1907), and some of these more recent attempts are 

 criticised. As to the relation of the formation to the association, 

 it seems to be accepted, with Warming, that the formation is 

 equivalent to an ecological genus, to which the association takes the 

 rank of species. 



There is also a summary of various methods of denoting asso- 

 ciations and formations, beginning with Schouw's suffix „etum" 

 on to Clement's recent elaborate terminology. While urging uni- 

 formity the author does not attempt any nevv scheme. The grouping 

 of formations into larger units also receives attention, especially the 

 attempts of Warming, Schimper and Graebner. The paper 

 includes an extensive bibliography, probabl}^ the most complete yet 

 published on the nomenclature of ecology. W. G. Smith. 



Novitates florae africanae. Plantes nouvelles de l'Afrique 

 tropicale frangaise decrites d'apreslescoUectionsde 

 M. Aug. Chevalier. (Suite). (Bull. Soc. bot. France. VIII. Mem. 

 sc. p. 111 — 136. juin 1910. A suivre.) 



Compositae. — Especes nouvelles decrites par O. Hoffmann 

 et Muschler: Erlangea Chevalieri du Congo frangais, Vernonia 

 Coiirtetii du Haut-Oubangui et du Chari, V. Klingi et Micro- 

 glossa cnudata de la Guinee frangaise, Laggera Lecomteana et 

 L. macrorrhisa du Haut-Chari, Sphaeranthus Lecomteanus et 

 Aspilia Chevalieri du Haut-Niger, A. sahariensis du Haut- 

 Oubangui, A. guineensis de la Guinee fran^aise, A. Courteti 

 du Bas-Chari, Melanthera rhornbifolia du Haut-Niger, M. Che- 

 valieri du Haut-Oubangui et du Haut-Chari, Coreopsis Cheva- 

 lieri du Bas-Chari, Lannaea Chevalieri des dunes de Tombouc- 

 tou, L. virgata et L. Coiirtetiana du Chari. 



Euphorbiaceae. — Especes nouvelles decrites par L. Beille: 

 Thecacoris Trilliesii (L. Pierre) du Haut-Chari, Th. Chevalieri, Me- 



