CiiAi'. I] CHARACTERS OV TIIK TEMPERATE CLIMATE 429 



Among the Myrtiflorac the Myrtaccae assume the first rank in llic 

 temperate as in the tropical zone ; they are confined to the mild-winter 

 belt, and only in Australia (for instance Eucalyptus) do they play 

 a prominent part. The Onagraceae are specially West American ' (for 

 instance Fuchsia), and llie Lythraceae, although represented everywhere, 

 are never dominant. Tunica inhabits warm temperate Western Asia. 



The Hysterophyia are .still less important in the temperate than they 

 are in the tropical floras. They are limited to a few Aristolochiaceae, 

 Santalaccae and Loranthaceae, and to one or two Rafflesiaceae and 

 Balanophoraceae. 



The Ericaceae possess social species in Calluna vulgaris and different 

 species of Erica, which compose extensive shrub-formations, termed heaths, 

 specially in the north cold temperate belts. Most of the species of Erica 

 are however indigenous in South Africa. North America also is very 

 rich in Ericaceae. The Epacridaceae are characteristic constituents of 

 the south temperate zone, specially in Australia, and never occur in the 

 north temperate zone. 



Of the three families of PriiiiiiUnae, the M}'rsinaceae are almost 

 absent from the temperate zones ; the purely mesothermic family 

 of Primulaceae exhibits numerous species, chiefly boreal ; and that of 

 Plumbaginaceae pla}-s an important part in steppes and deserts with .saline 

 soil and on the sea-shore, and it also is chiefly boreal. 



The Contortae possess an almost purely mesothermic group of forms 

 in the Gentianaceae, which, represented by species of Gentiana, inhabit 

 both the temperate zones ; also a mainly mesothermic family in the 

 Oleaceae, whose home is chiefly in East Asiatic and North American 

 forest districts. The families of Asclepiadaceae and Apocynaceae, which 

 are rich in forms in the tropics, become very subordinate in the temperate 

 zones ; the Loganiaceae are almost entirely absent. 



The Titbijiorae are, in their families Boraginaceae (with the exception 

 of the Cordiaceae), Polemoniaceae, and Hydrophyllaceae, mostly inhabitants 

 of the temperate zones, the Polemoniaceae and H\-drophyliaceae being 

 chiefly in America. The Convolvulaceae are less numerous than in the 

 tropics. 



The Scrophulariaceae include the main!}' mesothermic forms of the 

 Persouaiae, and are richly represented in both temperate zones ; while 

 the Solanaceac are much less numerous than in the tropics. The smaller 

 families of Orobanchaceae, Utriculariaceae, and Plantaginaceae are of slight 

 significance, and the almost purely megathermic large families of Bignonia- 

 ceae. Gesneraceae, and Acanthaceae have even slighter importance. 



Of the two families of the Labiatiflorae, that of the Verbenaceae is mainly 

 megathermic and of slight importance in the warm temperate belts only ; 

 whilst the Labiatae are chiefl)- mesothermic, and are represented by 



