22 Bews. — Some General Principles of Plant Distribution as 
Erica has over 500 species, of which 469 are endemic in South Africa, 
mostly in the south-west, but about 20 in Natal, most of them, but not 
all, in the Drakensberg. E. caffra occurs even on the subtropical coast- 
belt, and several are common in the midlands. Erica arbor ea connects 
through the mountains of Central Africa With South Europe, where there 
are about a dozen species, none of which are South African. Other 
sections of the family are, of course, American and Himalayan, &c. These 
facts are mentioned because they would seem to have an important bearing 
on the origin of the South African flora, and they certainly do not count 
in favour of the supposed land connexions with Australia and South 
America. The enormous number of Cape endemics belonging to the genus 
Erica provides an interesting field for investigation. Why, for instance, are 
so many of them concentrated at certain points, e. g. the Cape Peninsula or 
the Van Staden mountains ? 
While we are dealing with facts of this general nature, I shall quote 
what Schonland ( 29 ) has said concerning one or two other families. 
‘ The Penaeaceae and allied orders (the Thymelaeales) also fail to give 
us in their distribution an indication of their origin. Penaeaceae nearly 
allied to Thymelaeaceae ; only distinguished by 4-merous ovary with 2-4 
ovules each. All in South-West Cape Colony. 21 species and 5 genera. 
‘ Geissolomaceae, 1 monotypic genus, closely allied to Penaeaceae, with 
which the order has frequently been united. South-west Cape Colony. 
‘ Oliniaceae, fruit a drupe, while in the two previous orders the fruit is 
a capsule. About 6 species: 4 in Cape Colony, 1 in Usambara, 1 in 
Abyssinia. 
‘Thymelaeaceae, with the exception of the polar regions, distributed over 
the whole globe, but many genera and groups very localized. 
‘ Peddiea , 6 species. South-east and tropical Africa. 
* Gnidia } 80-90 species. Tropical and South Africa, Madagascar, and 
East Indies. 
‘ Struthiola , 24 species, mostly in South Africa, 3 in tropical Africa. 
‘ Crypt adenia, 4-5 species. Cape. 
‘ Lachnae a, 18 species. Cape. 
‘ Passerina , 4 species, and Chrymococca , 1 species. Cape ; 2 allied 
genera in central and northern Asia. 
‘ Dais , 2 species; 1 in Natal, 1 in Madagascar. 
‘ Eleagnaceae. Chiefly in the northern, temperate, and subtropical 
zone : none in the southern hemisphere. 
‘ The Bruniaceae, 12 genera and over 40 species, which are restricted to 
South Africa and even almost entirely to South-west Cape Colony, are so 
isolated among Saxifragaceae that we can also only point to their antiquity. 
About their origin no guess can be hazarded. . . . 
' There are a number of genera of large orders which must be placed 
