250 THE DISPERSION OF BRITISH PLANTS. 
11 individual species he names as instances of particularly wide d 
bution, 6 appear in our list, yet so far as the British flora is fs 
the degree of dispersion of salt-loving species, including those belong- 
ing to other orders as well as to the two named by Professor De Can- 
dolle, is less than that of other plants. 
ch 
es Average. 
111 _— e i é 6°32 
1040 Non-maritime 7:07 
This serepaiicy; ia other similar ones that will be met with here- 
after, no doubt partly arise from the limited scope of the present 
inquiry, co as it is to the British species alone, and from the 
entirely different metizeris by which the mean specific areas are asOr 
the present caltstons being based upon individual species, con- 
a each separately, and Professor De Candolle’s upon entire 
0 
Caleareous Plants.—Those plants that evince in Britain a preference 
for chalk te vee soils have a lower degree of dispersion oe our 
other plan 
Sree Average. 
Ls ge . . . . ° 5°43 3 
1070 Nei Caloatecth ‘ : . 712 i 
a species classed as calcareous comprise however no — ‘ ; 
alustral p ; and as we have seen that such are the widest 
rangers, a more correct — is perhaps one pr to ter 
restrial plants. It is as follow 4 
Species. Average. . 
81 Cal Oe ae 
758 Other terrestrials . jee 
On the other ar se aap plants iidtate an sie proportion of 
Orchids, an order that has only a limited specific range: omitting 
these again bi rier dihorelt re is:— 
Spe Average: : 
67 ee 5°60 fe 
735 Other terrestrials eg ae 
Heath Plants.—Species ae are F laaity haa on dry hoses 
moors, and co ommons, have also a rather limited degree of disper os 
i a. eae between them age other terrestrials being 
ows: 
Specie Aw 
35 Heath plants ‘ : d : Se ba 
799 Other terrestrials ‘ 6°60 
Dispersion in aneiin to Habit and ‘Duration. vis s 
Annu ‘ als, Biennials, and Perennials—The average areas a 4 
herbs, divided according to their qacatisn ; 
Perennials, while of the former Annuals hav 
than Biennials. British herbs give the following 
