2b THE GENUS CROCUS. 



and longitude (reduced to actual distance) of the average area occupied by each 

 species. 



Fig. 12. 



Looking at the prevalence of species and to their general wide distribution, 

 the district including Greece, the Greek Archipelego, and Asia Minor, must be 

 looked upon as the metropolis of the genus; for in these regions it forms a more 

 important feature in the flora than the outlying countries to which it extends. 



As a means of indicating in a concise form the general range of the species, 

 I propose to divide the region occupied by the genus into six sub-districts, repre- 

 sented by different shades of buff on the map; giving lists of the species occurring 

 in each, and expressing by letters the extension of the species of each district into 



neighbouring districts. 



The division into sub-districts may be to some extent arbitrary, but it has been 

 as far as possible ruled by natural geographical boundaries, or the ascertained 

 range of the more prominent species. Where a species is named in the sub-district 

 lists without a following letter, its occurrence is limited to that district; and where 

 the name of a species is followed by a letter, the letter indicates another district 



to which it extends. 



A. West European and North African district, including Portugal and Spam 

 the Balearic Islands, and France excepting the Alps, Marocco and Algeria. 



6. nudiflorus. '°- Clusii. 

 6.5granatensis. '3- Cambessedesii. 



7. asturicus. 2& - vermis. B. C. 



8. serotinus. +'• carpetanus. 



9. Salzmanni. 4*- nevadensis. 



Of these ten species in District A, only one C. vermis, extends beyond it to 



the east of the Rhone. 



B. Swiss and French Alps, Italy as far east as Venice, Sicily, Malta, Sardinia, 



Corsica, and neighbouring islands. 



14. Imperati. 22 - etruscus. 



15. suaveolens. *6- vernus. A. C. 



