E. V. Wulff —62— Historical Plant Geography 



ism; Briquet (1905) — "endemisme par conservation" and "en- 

 demisme par novation"; Deels (1908) — conservative and progressive 

 endemism; Herzog (1926) — relic or ancient endemism (Altersendemis- 

 mus) and neo-endemism; Braun-Blanquet (1923) and Chevalier 

 and Guenot (1925) — paleo-endemism and neo-endemism. The last- 

 mentioned terms seem to us the most suitable, and we have decided 

 to adopt them, despite the fact that, as Ridley (1923, 1925) has 

 pointed out, some confusion arises from the use of one and the same 

 term "endemic" to designate two different types of plants. Though 

 both are characterized by a restricted area of distribution, one type 

 embraces relics of earlier floras which have survived in a limited por- 

 tion of their past territory, the other type species having originated 

 in a given region and not yet having spread beyond it. In view of the 

 desirability of two distinct terms by which to designate these two 

 types, Ridley proposes to reserve for the second type the term "en- 

 demics", since they arose from parental forms on the territory of their 

 habitat and continue to live, so to say, among their own "demos" 

 (from which Greek word "endemic" is derived). In contrast to this 

 plants of the first type, being remnants or survivors of former floras, 

 he calls epibiotics. However, if the latter term is used, it seems to us 

 advisable to restrict its use to endemic relics {i.e., paleo-endemics) and 

 not to apply it to relics in general. 



To distinguish between these two types ordinarily does not present 

 any particular difficulty, since paleo-endemics (or epibiotics) do not 

 have any close connection with other species in their area, whereas neo- 

 endemics have numerous, often close bonds with other species in their 

 region of distribution. However, there are endemics which it may be 

 difficult to refer to either of these categories. For example, there are 

 instances of endemic genera, which without any doubt should be classed 

 as paleo-endemics but which comprise species that should be classed as 

 neo-endemics. These Rikli calls active epibiotics. 



The endemic flora of Australia, according to Diels (1906), consti- 

 tutes another example of the difficulty of referring endemics to the two 

 indicated categories. He divides this flora into three groups: (/) en- 

 demic genera not having any connection with pan-Australian genera; 

 often monotypical genera; (2) endemic genera having some connection 

 with the indicated genera; (j) endemic genera having undoubted con- 

 nection with pan-Australian genera. 



Endemic species are sometimes confined to exceptionally limited 

 areas, e.g., to a single mountain peak. Such species may be called 

 local endemics. Their greatly restricted areas may be due to one of 

 three causes: (/) the recent origin of the endemic, which has only 

 begun its dispersal and the formation of its area; (2) the antiquity of 

 the endemic, which is contracting its area, in consequence of which 

 the limited territory now occupied by it constitutes the last remnant 

 of its former area; (3) the specificity of the habitat conditions, which 

 prevail only in the given spot, or the impossibility of an expansion in 

 area due to obstacles of a physico-geographical nature. 



Braun-Blanquet (1923) distinguishes, in addition, micro-endemics, 

 which are endemic forms of lower taxonomic rank and recent origin. 



Lastly, we wish to mention pseudo-endemics, to which Herzog 



