Floristik, Geographie, Systematik etc. 663 



has been done in the present suggestive paper, wherein the author 

 inaugurates a new method of oecological study of plantformations. 



It is the value of the different species of a formation that is to 

 be expressed in figures. To make out this, the author counts all 

 the species found in a certain nurnber of samples of the same for- 

 mation, and the value of each species is expressed by the number 

 of samples in which it was found. He proceeds in the following 

 way: a frame whose surface measure is one tenth ofasquare meter 

 is thrown at haphazard fifty times, and for each throw all species 

 found within the frame are noted. Thus the dominating species 

 will be noted 50 times or only a little less, the rare ones only some 

 few times. Different methods and frames of different square measu- 

 res have been tried. Small frames and many throws give more 

 correct numbers than larger frames, this being controlled by shoot- 

 counting, but for practical use the author finds 50 throws of a 

 frame of one tenth Square meter sufficient. 



In order to make the thing clear we reproduce here one of (the 

 smallest of) Raunkiaers tables, giving the result of countings in a 

 facies of the flora of the danish beech-forest: 



Growth-form. Points. 



Aiva flexuosa H 49 



Majanthemum bifolium ... G 49 



Anemone nemerosa G 37 



Lusula pilosa H 19 



Milium effusum H 10 



Hievacium vnlgatum .... H 2 



H means Hemicryptophyte, i. e. plants whose buds are surviving 

 the winter in the surface of the soil, and G means Geophytes, whose 

 buds are subterranean. It may be seen that e. g. Aira flexuosa has 

 been found in 49 of the 50 samples, Hievacium vnlgatum only in 

 two. The rounded off values of the different species may then be 

 given as: 5, 5, 4, 2, 1, 0.2. In order to characterize the Vegetation 

 it is yet added that there are three species for each tenth square 

 meter, and that it is a geophyte-formation, 52 per cents of the points 

 belonging to geophytes, a very high number compared with the 

 percentage of geophytes in Den mark as a whole. In this way 

 systematical units are inverted into biological ones. a species-list 

 giving the biological relations of the formation. And these numbers 

 and relations, compared with corresponding ones from other vege- 

 tations, may serve as means for -a numerical limitation of formations. 

 Proceeding in this way the author describes a certain number 

 of danish plant-formations, giving 43 tables and many further details 

 besides photographs of some formations. Of the many items here 

 communicated the following may be quoted. 



In the beech-forest the different facies are composed mainly of 

 geophytes, in the spruce-forest of hemicryptophytes. In high-moors 

 the formations are characterized by chamaephytes (whose surviving 

 buds are situated on or a little above the surface of the soil), and 

 this the more the higher the elevation over the water-level. The 

 heath in its different formations and facies has a Vegetation of cha- 

 maephytes or of small phanerophytes (buds on branches in the air), 

 the last ©nes dominating in the J/y/"/Crt- formation. Salicornia forms 

 the only spontaneous Therophyte (annual) formation of Denmark; 

 Hemicryptophyte-formations (e. g. meadows) are both richer in spe- 

 cies and more compact than the other formations. Ove Paulsen. 



