INTRODUCTORY ESSAY. 27 



and the Malay peninsula and islands, produce an abundance 

 of well-marked species of plants, whilst the dry, hot, lower 

 hills of Central India, with contrasted seasons, produce com- 

 paratively few, and none presenting any great difficulties to 

 the systematist ; as also that the plains of the Gangetic valley 

 and of the peninsula, which have marked seasons, are com- 

 paratively poor in species, whilst those of the Cape, Australia, 

 and South America, also having decided summer heat and 

 winter cold, abound in species. Such discrepancies prove how 

 subtle an element climate is, and how extremely cautious the 

 naturalist should be in generalizing upon its effects. They 

 especially warn us not to consider the influence of climate as 

 paramount in determining the distribution of species or pre- , 

 valence of forms. We learn from them also that the primd 

 facie evidence in favour of definite creations is not to be lightly 

 put aside ; and they suggest the propriety of instituting ob- 

 servations in proportional botany, as that branch of the science 

 may be called, which develops the relations between the num- 

 ber of orders, genera, and species, contained in an area, and its 

 climate and other physical characters. 



And now that we are on the subject of variation, it ap- 

 pears advisable to impress upon the Indian botanist the value 

 of studying its phenomena in the field. We pledge our ex- 

 perience that he wiU find it the most profitable department of 

 systematic botany he can pursue; and that the result of his 

 investigations will be that he will take a wide and extended 

 view of the variations of species, consistently with their still 

 possessing certain definable limits. We shall offer a few re- 

 marks on this point under two heads : — variation of parts of 

 the same individual, and variation between different indivi- 

 duals of the same species. 



1. Variation in organs of the same individual plant. From 

 the luxuriance of the vegetation with which the Indian bo- 

 tanist is so often surrounded, and the rapidity of its develop- 

 ment, he has advantages for pursuing this inquiry that ob- 

 servers in colder climates do not possess. In general terms. 



