Australian Floioeriny Plants. 217 



The Epacridaoese are peculiarly xerophytic, having leaves 

 either small terete, acicular, pungent, grooved, thick or hard, 

 and they are trees, shrubs, or undershrubs, which are confined 

 principally to moist situations on the barren sandstones of extra- 

 tropical Australia. They are as much an integral part of the 

 indigenous, endemic, xerophilous, flora of Australia as are the 

 Proteacese, and the Myrtacea?. 



Ericea?, in Ericaceae, has its stronghold on the sandy barren 

 wastes of Southwest Africa. Erica, is only one of the many 

 allied genera in that country, Erica itself, however, possessing 

 there nearly 500 endemic species. This genus, however, does 

 not favor wet situations as much as the Epacrids do. Erom a 

 consideration of the distribution and the morphology of the 

 families, it would appear that both families sprung from com- 

 mon ancestral types which were luxuriant trees, especially in 

 the great northern lands, and in the tropics possessing leaves 

 either nerved or penniveined, stamens free, anthers 5 to 10, 

 with two cells opening longitudinally in slits and without 

 appendages. 



In the first great radiation these types reached Australia 

 and South Africa. After the isolation of Australia and South 

 Africa they retreated to the sandy wastes of the two countries. 

 In Australia they became the Epacrids, in South Africa the 

 Ericas. In each country they developed a great crop of vigor- 

 ous and aggressive genera. During the second great differentia- 

 tion of climate in the northern hemisphere, the other large tribes 

 of Ericaceae became strongly developed in the cold countries 

 contemporaneously with Senecio, Aster, and other types, in 

 Compositse. 



The newer cold types of the north, as Gaultheria, travelled 

 . south during the Glacial Period to the extreme south of 

 America. Waifs thence were carried by the great westerly 

 drift or by other means to Australia and New Zealand, develop- 

 ing in those countries a very few individuals belonging to two 

 or three genera. (Gaultlieria, 3 species, Pernettya, 2 species.) 

 The genus Wittsteinia, one species only and belonging to the 

 tribe Arbutese, may be a waif, or it may be a relic of the old 

 Cretaceous radiation. 



(5) Campanulacew (with Lobeliacece, and allied families). 



The Campanulacese and its allies are good examples of the 

 two-period differentiation of climate. From an examination 

 of Campanulaceae, Lobeliacese, Goodeniacese, and Candolleacese 

 generally, and of the peculiar arborescent Lobeliacese of Hawaii 



