35^ 



C. SKOTTSBERG 



1. hi all cases considered floristic relations exist beiiueen the island and one 

 mother continent. 



2. The floras of all the islands in qiiestion are more temperate in character 

 than that of the mother continent on the same latitude. 



This may be true in most cases tlianks to the influence of the surrounding 

 ocean; it holds good for Juan Fernandez. 



3. All these isla)ids show matiy biological peculiarities by which they are 

 distinguished. 



The distinguishing characteristics are mainly expressed in endemism. HoOKER 

 referred the endemics to two categories, such as do not show affinity to the plants 

 on the mother continent, and such as, even if belonging to endemic genera, are 

 related to continental ones. 



If we turn to the Pacific where, for obxious reasons, only the high volcanic, 

 well-watered islands are considered, we find that all of them are distinguished by 

 numerous, in many cases also very remarkable endemics. Hawaii stand out above 

 the others and so do Juan Fernandez and Desventuradas; the floras of Tahiti, 

 Samoa, Marquesas etc., as well as of Micronesia, are less independent. The degre 

 of spatial isolation is not conclusive; the flora of Juan Fernandez is more peculiar 

 than that of Marquesas which are situated- much farther away from any continent, 

 and this holds good not only for the angiosperms but also for the ferns. En- 

 demism in angiosperms is 69% in the former and 50 in the latter; of the ferns 

 about 30% in each, but only Juan P^ernandez has an endemic genus. 



4. The general rule is that the species also found in the mother continent are 

 the most abundant, the peculiar species are rarer, the peculiar geiiera of contijiental 

 affinity rarer still, but the pla)its with 710 affinity elsewhere are often very common. 



This is, I suppose, true of the islands examined by HoOKER, with the 

 exception of St. Helena before the arrival of man, but not of Hawaii, nor of 

 Juan Fernandez. Some of the continental species — Lihertia and a few grasses — 

 are abundant, while others are rare, all according to the supply of suitable 

 habitats; among the peculiar species of continental affinity are many quite 

 common ones, e.g. the endemic species of Acaena, /Jrimys, Dysopsis, Es- 

 callonia, Gumiera, Myrceugenia (the leading forest tree on Masafuera), Pernettya, 

 Rhaphithamnus, Ugni, Erigeron fruticosus, Uyicinia Douglasii\ and of the peculiar 

 genera allied to South American ones, Nothomyrcia is the leading forest tree 

 on Masatierra, where Ochagavia is also common. To these may be added such 

 common endemics as Boehneria and the species of Fagara and Coprosma, under 

 the assumption that related species oi Boehmeria, and representatives of Coprosma 

 and Fagara, once belonged to the neotropical flora. The plants of no affinity in 

 the mother country, that is the nearest continent, are as a rule very local, few 

 are common and many extremely rare. 



Possibly I have misunderstood HOOKER here. When we say that a species 

 is abundant in a country we mean that it is copious; if we call it common, it 

 is widely spread; if we call it rare, it has been reported from a small number 

 of localities only; and if we use "species" in plural we mean the same thing. 

 But what if Hooker with "abundant" and "common" wanted to say that these 



