TRANSACTIONS OF WAGNER 
VEGETATION OF SOUTH FLORIDA 
184 
phytogeographers* upon the coefficient of community. The ratio of the 
number of species common to two districts to the total number of species in the 
two districts taken together is their coefficient of community. This is derived 
as follows: 
EM Costera РЕ ries ошоо a 
Total number of species in the 2 districts 
Adding then the total number of species in the Flora of Miami (878) and the total 
number in the Flora of the Florida Keys (627), we have as the denominator, 
1505, the total number of species in the two districts. The total number of 
species common to the Miami region and the Florida keys is 282, as obtained 
282 vs O 
1505 X100= 18.73 . 
The coefficient of community for the two districts in South Florida is 
18.73 per cent. Thus in spite of their proximity and the somewhat similar 
from Small's Flora of Miami. Hence, we have 
ecologic conditions, the flora of our two districts possess very different com- 
positions. 
ECOLOGIC ANALYSIS 
Growth Forms.—In the classification of growth forms, 1 have chosen the 
system of Raunkizr,] because, in spite of its one-sidedness it emphasizes one 
of the most important features of plant life, and because it is easier to handle 
than other classifications of growth forms, and it is possible to express statistic 
data in comparison with other regions. The biologic types (growth forms) of 
Raunkizr are arranged according to the way in which plants live through the 
unfavorable seasons of the year, and emphasis is put upon the degree and the 
kind of protection afforded to the dormant buds. In countries where the con- 
ditions are favorable, the dominant plants are phanerophytes (Ph.), their buds 
being found on aérial branches. This group includes trees and shrubs. Ac- 
cording to the height of the phanerophytes, Raunkiær divides them into 
mega-, meso-, mikro- and nanophanerophytes. The chamæphytes (Ch.) are 
those plants with dormant buds on the surface of the ground, or just above 
it. In the former case, they are plants with superficial, creeping and persistent 
shoots; in the latter case, they are cushion-plants, or undershrubs. The 
hemicryptophytes (H.) have dormant buds found in the upper soil layer, just 
below the surface, while their aérial shoots are not perennial. The fourth 
* Jaccard, Paul: The Distribution of the Flora in the Alpine Zone. The new Phytologist, xi: 
39, Feb., 1912. 
{ Raunkier, C.: Types biologiques pour la geographie botanique. Bull. Ac. Roy Sc. Dane- 
mark, 1905; Statistik der Lebensformen als Grundlage für die biologische Pflanzengeographie. Beitr, 
Bot. Centralbl., 27 (1910): 171-206d. 
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