Geology and Natural History. 147 
19. Three Essays relating to Vegetable Paleontology are before 
1.) Area. DeCanpDotte, on Physiological Groups in the Bh rid 
le Régne Veg de Groupes 
ble Kingdom: ( Constistution dans egn étal 
Physiologiques applicables a la poten te Botanigque ‘Aneta 
et Moderne}; par M. ee DeCanpo.ie.—An article of 38 
pages in the Archives des Sciences de la Bibliothéque Universelle, 
Geneva, of May, 1874, and sient separately. M. DeCandolle here 
makes an attempt to mark out groups of plants according to the 
— which they affect. 
m the i of err asses, familie, to their botanical char- 
this want M. DeCandolle here itches to ou Lith 
ture, These 
terms Xero plants, lovers of dryness. They are pretty 
the sowing - say a mean anneal tempera rature of 59°-68° 
that of “0 wit h of ¢ a good su P ceawie In this 
group would be eothetry the ciel <a our Northern States 
and Canada. 
e fifth group, Hekistothermal plants, those requiring least 
heat, such as make up arctic, antarctic, and less vegetation. 
ds, 1, 
e present Eatzibation of . over the globe depen 
upon the distribution in a preceding epoc och, and 2, upon the physi- 
cal conditions, mainly the distribution of heat and moisture, now 
existing. These conditions have varied greatly ; and under them 
