486 ON THE ODOURS OF PLANTS. [April, 



some forms^ beautiful colours, and in numerous instances delight- 

 ful perfume. It is to this latter principle of their character that 

 we shall at present invite attention. But although some are re- 

 markable for their aromatic odours, others are not less repulsive 

 by their disagreeable smell ; while the fragrant effluvia emanating 

 from others court our regard, the great offensiveness of others 

 is almost unbearable. On the other hand, a number, and I be- 

 lieve the greater part, of the vegetable tribes is totally devoid of 

 any appreciable odour whatever; with these scentless plants we 

 shall in the meantime have nothing to do. It is to those species, 

 and those alone, whose odours produce an agreeable or offensive 

 impression on the olfactory nerves, that the following remarks 

 are devoted. 



As far as my own experience is concerned, the odours of plants 

 and flowers have never been employed as a means for the deter- 

 mination and distinction of closely allied species. Some botanists 

 have employed one character, some another, as peculiar to this 

 or that species ; but never have I read of any appealing to the 

 odour as a means of determination. It is however only in closely 

 allied species that recourse to this property is really necessary. 



From several years' practical experience and observation, I have 

 satisfactorily ascertained that the odours peculiar to certain plants 

 are permanent and unchangeable, under all ordinary circum- 

 stances of vegetable life, whether such individuals are wild or 

 cultivated. What I mean to assert is, that the odours of plants 

 are co-extensive with the life of the individual, and prior to ma- 

 turity in some, and during the period of decay in others, is more 

 or less powerful in different species. 



The common Woodruff of our woods and plantations is nearly 

 scentless until dried, when the odour becomes agreeable and 

 peculiar, resembling in no small degree that of the Tonka Bean, 

 the fruit of the Dipterix odorata, a member of the Leguminifera 

 and an inhabitant of the umbrageous forests of Guiana. 



A very i-emarkable and prominent example of odoriferous plants 

 is supplied by the genus Melilotus, one of the genera of this great 

 Order. All the Melilots smell strongly in the herbarium, and 

 this odour is very permanent. One of them, M. coeruleus, is em- 

 ployed by our Continental neighbours in the manufacture of snuff ; 

 others of this species are used for the colouring and flavouring of 

 cheese. The powerful odour of Fenugreek is notorious. 



