12 ASSOCIATION 



The term formation was proposed by Grisebach in 1838; 

 he defined the concept as follows: "Ich mOchte eine Gruppe 

 von Pflanzen, die einen abgeschlossenen physjognomischen 

 Charakter traegt, wie eineWiese, ein Wald, etc., eine pflan- 

 zengeographische Formation nennen. Sie wird bald durch 

 eine einzige gesellige Art, bald durch einen Complex von 

 vorherrschenden Arten derselben Familie charakterisiert, 

 bald zeigt sie ein Aggregat von Arten, die, mannigfaltig 

 in ihrer Organisation, doch eine gemeinsame Bigenthuem- 

 lichkeit haben, wie die Alpentrif ten fast nur aus perennier- 

 enden Krautern bestehen. " Before Grisebach's time, 

 several writers had perceived the essential correspondence 

 between habitat and vegetation, though they did not recog- 

 nize the fundamental importance of this relation. Linnc 

 mentioned a few generalized stations in i^oraiopponica (1737) 

 and Flora Suecica (1745), but in the Philosophia Botanica (1751 : 

 265) he not only distinguished the following twenty-five hab- 

 itats, but also characterised each briefly and listed the prin- 

 cipal genera : mare, littora, f ontes, fluvii, ripae, lacus, stagna, 

 paludes, cespitosae, inundata, uliginosa, alpes, rupes, montes, 

 campi, sylvae, nemora, prata (a. fertilia, b. exsucca, c. 

 humidiuscula), pascua, arva, agri, versurae, culta, fimeta, 

 ruderatae. In addition, he arranged stations in four groups 

 with respect to the kind of soil, viz., humus, arena, (mobilis, 

 farinacea, vulgaris, sabulosa), argilla, creta. 



Hedenberg (1754:73) recognized twenty -four stations, 

 naming them after the specific names of characteristic 

 species, and classifying them in five groups as follows: 

 Aquaticae; (1) Marinae (2) Maritimae (3) Lacustres (4) 

 Palustres (5) Inundatae (6) Uliginosae (7) Caespitosae; 

 Alpinae, (8) Aetberea (9) Occlusae ; Umbrosae, (10) Nemo- 

 rosae (11) Sylvaticae; Campestres, (12) Arvenses (13) 

 Cultae (14) Ruderales (15) Pratenses (16) Arenariae (17) 

 Argillaceae (18) Cretaceae; Montanae, (19) Glabretosae 

 (20) CoUinae (21) Rupestres; Parasiticae (22) Arboreae 

 (23) Herbaeeae (24) Radicales. Each station is described 

 briefly, and the veeretation usually characterised in a few 

 words, e. g., ;"10. Nemorosae. Loca Nemorum sub arboribus 



