. On the Colour and Smell of Plants. 19 



green, we meet with no odoriferous species, or so few that they 

 cannot be employed for general results. We perceive, again, 

 that white plants have the greatest tendency to be odoriferous, 

 and blue plants the least. 



By deducing a general mean from the previously communi- 

 cated observations, in connection with the results obtained 

 from the Rubiaceae, we obtain the following division of colours 

 and odours : 



Species having a disagreeable odour are rare in this family, 

 and chiefly in the genus Mephitidia, the colours of whose flow- 

 ers have, however, not been very particularly ascertained. 



In examining more closely the species of this great family, 

 in regard to colour and smell, we find, as to the first, that white 

 also predominates here, except in the Cinchoneae, in which the 

 red colour is the most abundant, for they contain, taking the 

 mean, 41 red and 38 white flowering species. The red is, after 

 the white, the most prevailing colour in the Gardenias and the 

 Hedyotideae ; the yellow in the Stellatae and the Guettardaceae ; 

 the blue in the Spermacoceae, which also include several species 

 having a disagreeable odour, and which act powerfully on ani- 

 mals. The Coffeaceae have, next to white, the greatest tendency 

 to red and yellow flowers, although some genera contain also 

 violet flowering species. The Gardeniae and Cinchoneae, which, 

 next to white, are chiefly disposed to red tints, contain the 

 largest number of species having an agreeable smell ; and the 

 Spermacoceae, which, next to white, have the greatest tendency 

 to blue flowers, possess the fewest. 



By arranging the great genera of the Rubiaceae for the cal- 

 culation of their relations of colour, according to the rules al- 

 ready laid down, we obtain the following tabular views : . 



B* 



