Mimicry among Plants. 99 



herbivorous animals may have the same taste and that in all 

 probability the parasitic plant would thus escape their attacks. 



The other example of apparently real mimicry is described by 

 Burchell nearly one hundred years ago. In his travels through 

 the karroo he found a species of Mesembrianthemum, which he 

 named M. turbiniformc, thinking it to be undescribed. As a matter 

 of fact it had been found by Thunberg, who had named it M . truncatum, 

 from the shape of its leaves. Burchell * gives the following account 

 of his find : " On picking up from the stony ground what was sup- 

 posed a curiously shaped pebble it proved to be a plant, and an 

 additional new species to the numerous tribe of Mesembrianthemum; 

 but in colour and appearance bore the closest resemblance to the 

 stones between which it was growing. On the same ground was 

 found a species of the Gryllus tribe amongst the stones, and so 

 exactly like them in colour and even in shape, that it could never 

 have been discovered had it not been observed just at a moment 

 when in motion. The intention of Nature, in these instances, seems 

 to have been the same as when she gave to the Chameleon the 

 power of accommodating its colour, in a certain degree, to that of 

 the object nearest to it, in order to compensate for the deficiency 

 of its locomotive powers. By their form and colour, these insects 

 may pass unobserved by those birds, which would soon extirpate 

 a species so little able to elude its pursuers, and this little Mesem- 

 brianthemum may generally escape the notice of cattle and wild 

 animals." 



This plant has been referred to by Wallace f as the stone Mesem- 

 brianthemum of the karroo, and its case is mentioned as the only 

 example of real mimicry that has come to his notice. 



As stated at the beginning of my paper, I was at first very scep- 

 tical about this and similar statements, particularly as cattle, which 

 Burchell mentions, are not indigenous to the country. Gradually, 

 however, my observations of such cases have become more 

 numerous, hence I cannot look upon them all as mere coincidences. 



The most remarkable plant in this respect is MesembriantJicmiim 

 Boliisii, Hook, f., which inhabits the hills of the karroo about 

 Aberdeen. It generally produces only two leaves, which grow to 

 the size of a duck's egg. Their surface is rough like weathered 

 stone and their colour a brownish grey with a touch of dull green. 

 The leaves are half buried in the soil or between the stones among 

 which the plants grow, hence it requires a keen eye to detect them 



* Burchell, " Travels in the Interior of Southern Africa," London, 1822, vol. i. 

 p. 310. 



f Wallace, A. E., " Tropical Nature and Other Essays," London, 1878, p. 223. 



