MARINE ALG.E FROM THE KERMADECS 17 



forms are evolved or produced which, hy their purely physiological 

 origin, are evolved alone by physiological stimulus, and are not 

 perpetuated, or their origin may be pathological. Whilst a variety 

 may be defined as a variation of some important morphological 

 or structural significance, which persists alongside of a type 

 from which it was manifestly derived, the status of a " form," 

 "state," &c., must be regarded as inferior to those differences in 

 individual species which are called varieties. This is because 

 permanent variations are useful adaptations, whilst forms or states 

 are merely ephemeral reactions to stimuli called forth by a dis- 

 organized state, an abnormal environment, or the effect of ad- 

 jacent species. The ultimate test of species, variety, or form is 

 found only by cultivation for several generations, and this in the 

 present instance does not appear to have been done. 



The greater plasticity of plants (compared with animals) 

 renders them more liable to become abnormal, and open to the 

 attack of other plants. This is well illustrated in the case of 

 microscopic fungi, e. g. rusts, smuts, where the condition they 

 induce is closely analogous to the white coloration of the under 

 surface of Spiraa Ulmaria. It may be due perhaps to the plant's 

 inability to manufacture its food-substances, and to answer fully 

 to the stimulus of chlorophyllization, which is stimulated exter- 

 nally and produces an inner derangement. 



To sum up, species are the biological units once differentiated 

 by variation, which goes on complicating original differences, so 

 that permanent varieties occur, and at the same time plants are 

 open to detrimental effects of environment and resulting reaction, 

 often impermanent, as here. These must not be confused with 

 permanent intermediate forms obtained by hybridization and 

 crossing, which remain constant, and are produced by definite 

 interbreeding. 



When species, variety (so-called), and an intermediate state 

 are commingled in the same unit, it is reasonable to suggest that 

 the two last are of no permanence, and in this case that the 

 denudata form of Spircsa Ulmaria is a malformation. 



MAEINE ALG^ FEOM THE KEEMADECS. 



By a. & E. S. Gepp. 



The following is a list of marine algge collected by Mr. 

 Eeginald B. Oliver, of H.M. Customs, Christchurch, New Zealand, 

 during his visit to the Kermadec Islands in 1908. An account of 

 the vegetation of the islands is published by him in Trans. New 

 Zealand Institute, vol. xhi. 1909, pp. 118-175, in which he gives 

 a history of the past botanical investigation of the Kermadecs, a 

 description of tlieir Geology, Climate, Introduced Animals and 

 Plants, Plant Formations, Geographical Distribution, kc. The 

 following facts are largely derived from his paper. 



The Kermadec Islands are four — Sunday Island or Eaoul 

 Journal of Botany. — Vol. 49. [Jan. 1911.] c 



