Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 10. 1981. (Budapest, 1981)

Fig. 1. Map of the localities In the following possibilities of semiquantitative and quantitative evaluation will be presented with the afore-mentioned three floras used as examples. The method will be presented not as a unique one but as a possible one, applicable also in palaeontology. Two biocoenoses can be compared by means of the JACCARD (1908) and S0RENSEN (1948) Indices: C K = N

1+

N

2-C K: Jaccard coefficient G: the number of the common spécii in the two floras or faunas N^: the species number of the first flora/fauna Ng: the species number of the second flora/fauna The Sirfrensen-index: 2n C = C

B

: the Síírensen-index njij: the number of the common spécii nj: the species number of the first flora nk: the species number of the second flora As It Is Been, both equations operate only with total Bpecles number and the number of the mutual spécii. K and C

8 can range between O and 1. If the floras compared contain no common spécii, it is O, if they agree completely, it is 1. The following equation can be regarded as a variety of the Sjrfrensen-index: C

«ioo = ^b" 100