THE VEOETAl'ION OF THE JUAN EERNANDEZ ISLANDS 825 



CllAI'TER II. 



The Life -forms. 



In my first report on the flora ( ?. 53 — ^54) I tried to construct a biological 

 spectrum, using the method invented by C. Ralnkiaer, in order to find out 

 whetiier or not, in the case of Juan Fernandez, the spectrum was an expression 

 of one of liis phmt cfiniates. I came to the result that this was not the case; the 

 spectrum seemed to be anomalous, and I tried to find the reason. Our 1916 — 17 

 survey added a great number of endemic species and several non-endemics not 

 found before in the islands. Further, I had an opportunity to study the morphology 

 and behaviour of practically every vascular species in the field, enabling me to 

 refer them to the life-form classes with greater exactitude (Table XVII). Abbrevi- 

 ations are according to Raunkiaer with the slight difference that Me stands for 

 Mesophanerophyte — there are no Megaphanerophytes in the islands; both are 

 taken together by Raunkiaer as MM — and that Mi instead of M is used for 

 Microphanerophyte. 



On the basis of this material the spectrum set forth in Table XVIII was 

 constructed, and compared with a "normal spectrum" based on looo species 

 instead of 400 (Raunkiaer 5). 



The main difference between the two lies in the larger percentage of N and 

 Ch, the smaller percentage of Th and the absence of G in the islands. As we shall 

 see later, typical H are not so well represented as the figure seems to indicate. 

 Compared with my old figures the main difference lies in the rise of Ch from 13 

 to 25.3 % and the fall of H from 30 to 22 %. The rise of Ch is caused partly 

 by the removal of a number of H to Ch, partly by the character of the flora 

 above the timber-line in Masafuera, which was little known before 191 7: of the 

 21 species restricted to this region 14 (66 2/3 %) are Ch and 7 (33 1/3%) H. 

 If we want to compare the plant climate and spectrum of Juan Fernandez with 

 other climates and spectra it is recommended to treat Masatierra (incl. Santa 

 Clara) and Masafuera separately. The result is accounted for in Table XIX. 



With regard to Masatierra, the figures greatly exceeding the corresponding 

 ones in the normal spectrum are the figures for N and Ch, but as the Ch do not 

 reach 20 %, they need not occupy us here, while the Ph deserve special attention. 

 The percentage approaches the figures known from the Ph climate of the tropical 

 zone with not too small rainfall (Raunkiaer 2. 79). Thus we have reason to com- 

 pare the spectrum for Masatierra with some tropical spectra published by Raunkiaer 

 1. c, and this I have done in Table XX. Unfortunately, Raunkiaer's figures were 

 based on old lists, but even if later additions had been considered it is hardly 

 probable that the spectra would have turned out very different. 



The principal difference between Masatierra and these tropical islands lies in 

 the higher percentage of H and the low percentage of Th, but H are far from reaching 

 a figure characteristic of a Hemicryptophyte climate (50 % and over). To judge 

 from the spectrum, Masatierra is expected to have a subtropical climate, but we 

 have seen that it is warm-temperate, and this may be concluded also from the 

 cultivated plants (Johow 7). Hardy things like apples, pears, cherries, raspberries, 



55 — 516796. The Nat. Hist, of Juan Fernandez and Easter Isl. Vol. II. 



