K.— BOTANY. 195 



can be shed on the true nature of what may have been regarded as a large 

 ' compound-species ' or a host of small, closely-allied ' micro-species.' 



Until I had the opportunity of visiting New Zealand I was not very 

 greatly exercised about the problems underlying the species question, and 

 was content, like others, to describe a new species without any particular 

 qualms from a single specimen. 



The extraordinary prevalence of hybridisation, however, in the New 

 Zealand flora, seen under the able guidance of Dr. Leonard Cockayne and 

 Dr. H. H. Allan, quickly made me realise how rash it would be to think 

 of describing any New Zealand plant as belonging to a new species with 

 only a single specimen before one. 



Later, when on Rainbow Mountain, I found the erect shTuhhy Gaultheria 

 oppositifoUa, with its dry calyx and dry fruit, passing imperceptibly through 

 an infinite number of intermediate forms into the prostrate alternate- 

 leaved G. depressa (or G. antipoda), with red or white fleshy calyx-segments 

 enclosing the fruit, it became clear that the question of 'species,' 

 'Linneons,' ' Jordanons,' and the rest, was a burning one, requiring the 

 collaboration of the Systematic Botanist, the Ecologist and the Geneticist 

 for its solution. 



Here, then, is a large and vital problem which, to my mind, very greatly 

 widens the interest and importance of our Herbarium studies, since 

 problems relating to the possible hybrid origin of the plants we are dealing 

 with demand careful study in the field, with visits to the countries where 

 the plants are native. 



I am reminded, from what I saw in New Zealand of the ' hybrid 

 swarms ' in Gaultheria, Nothofagus, Myrtus, Veronica (Hebe), and many 

 other genera, of that remarkable Malvaceous genus Nototriche,^ native of 

 the Andes of South America. At the summit of the pass leading from 

 Peru into Bolivia I collected, at an altitude of about 14,500 feet, some five 

 quite distinct ' species,' growing close together under apparently identical 

 conditions of soil. They were easily separable by their leaf and floral 

 characters, but I wondered then, and I wonder now, why there were these 

 five distinct forms in this small area, when apparently any one of them 

 was good enough and perfectly adapted for the perpetuation of the genus ! 



Dr. Lotsy, I feel sure, would regard them as hybrids or of hybrid origin, 

 and, unless we feel inclined to assume that Nature has evolved this multi- 

 plicity of forms for pure pleasure — a sort of botanical experiment in 

 permutations and combinations— it is difficult to lay aside the view that 

 hybridisation, in this genus and possibly in many other genera, has played 

 a prominent part in the development of the multitude of described ' species ' 

 we see around us. 



These tiny prostrate plants were many years old with deep tap roots, 

 and they would be well-nigh impossible subjects for experiment, like so 

 many of the remarkable South African examples to which Dr. Lotsy has 

 so forcibly drawn our attention. 



Then again the visitor to Australia cannot fail to be impressed by the 

 multitude of ' species ' in the genus Eucalyptus. The study of the literature 

 is no less bewildering than is the study of the living trees, and we must, 



2 A. W. Hill in Trans. Linn. Soc. (Bot.), ser. II, vol. vii. 1909. 



02 



