By the Hon. and Rev. William Herbert. 41 



Mules are not often produced naturally, at least in Eu- 

 rope, (except in gardens, where plants are brought together, 

 which could not otherwise have mingled) perhaps because 

 all the combinations that were likely to occur in the native 

 situations, have been made centuries ago, and have taken 

 their place in the catalogue of species; whereas local species, 

 which may have been produced by diversity of soil or cli- 

 mate, are often brought in contact by cultivation. The only 

 sterile mule, in a wild state, of which I have heard, is Cen- 

 taurea hybrida, which grows upon a hill close to Turin, 

 where it is supposed to be produced by the frequent inter- 

 mixture of two species of Centaurea, and to bear no seed 

 itself. Ranunculus lacerus, also sterile, has been produced 

 accidentally at Grenoble, and I believe near Paris, by the 

 union of two Ranunculi ; but this occurred in gardens. I 

 cannot learn that any attempt has been made to touch their 

 stigmas with their own dust, or that of one of their respec- 

 tive parents ; or to ascertain whether there is any deficiency 

 in the pollen or ovarium. 



I have already mentioned that the stigma of Liliaceous 

 plants is furnished with a fringe of transparent tubes, by 

 which the juice of their own dust is probably taken in ; but 

 I have occasionally observed in Crinums one or two such 

 tubes on the side of the style, and even close to its base, 

 which is concealed within the long tube of the flower : and 

 I see no reason to doubt the possibility of the germen being 

 fecundated through their means, if the stigma were cut off, 

 and the liquor expressed from the dust were to reach them. 

 On examination of the flower of Morea tricuspis in a mi- 

 croscope, I discovered, near the base of the opposite petal, 



VOL. IV. G 



