Books and Current Literature. 147 



characteristic Mediterranean plants, ^vhile the Jnl\- temperature 

 inlluences that of the middle iCuroiJean plants ocnrring in the 

 regions studied. The isotherm of five degrees C. for January 

 fixes the npper limits of the Mediterranean vegetation, and- the 

 isotherm of ten degrees for July that of the forest; th.e upward 

 curve of these isotherms defining in general the upward exten 

 sion of the altitude limits in question. The annual ])recipita 

 tion has a positive inlluence on the altitudinal limits of the 

 middle European forest trees, while its inlluence on the xero- 

 l)hilous representati\cs of the .Mediterranean vegetation is for 

 most part negative. The altitudinal limits of nearly all the p'anls 

 studied rise on api)roaching the African desert region, the con 

 tinental lartsof Asia and the I'\ reman i.eninsula; while in gen 

 eral the least upward extension is oljserved in. the Apennines 

 and in the Balkan i eninsula. — \'. M. vSpai.dixc. 



Tiir: PilWT Di-posits < ii- Im.orii).\.- Tlar])er has published 

 a rejort '■' of his reconuaisance of the ]jeat de] osits and peat- 

 forming areas of I'lorida. In addition to a considerable mass 

 of information relative to peat, the re] ort contains the best 

 descrij^tion of the vegetation of iHorida which has yet been 

 made. I'ourteen 'natural divisions" of the stale are outlined 

 by maj) and brieily characterised as respects their topography, 

 soils and vegetation. '1 he low elevation and immature topog- 

 raphy of I'lorida give rise to a Ijcwildering variety of palustrine 

 areas, which have naturally received more attention in this 

 ])aper than the upland vegetation. Harper has described some 

 27 tyj^es of marshes, swam])s, bogs, "])rairies," "baxs" and 

 other formations with wet substratum. He has used the charac- 

 ter of the vegetation in distinguishing these areas and has fol- 

 lowed the refreshing custom of giving them either such names 

 as are locally used for them or else simjjle designations that are 

 descriptive of their \egetation or their most ob\ious pli\sical 

 characters. The alluvial and estuarine swamps and marshes 

 appear to be clearlx differentiated from those in which the water 

 is calcareous, the latter .uroup eml)racing the great 

 majority of the areas described. Also of imi)ortance 



*Hurper, Roland M.. Preliminary Report on the Peat Deposits of I'-lorida Third .\uu . 

 Rep. ria. State Geol. Sur\-., pp. PJ7, pis. 17-28. figs 17-30. 1 map. 1910. 



