W. Travers. — On the Origin in N.Z. of Polygonum aviculare, L. 313 



by tlie whalers, or amongst those of the various plants which were brought 

 down by the Greenwoods and others mentioned. 



With regard to the silence of D'Urville, Fraser, Allan Cunningham, and 

 Lesson, it must be remembered that all these observers saw the extensive 

 cultivations of the missionaries at the Bay of Islands and elsewhere, and if 

 they did notice Polygonum aviculare at all, they would probably look upon it 

 as having been introduced amongst the other European seeds which they saw 

 flourishing there. In this connection Mr. Kirk will probably call to mind the 

 interesting description given by Darwin of the appearance of the mission 

 station at Waimate, in 1836, and no doubt any English botanist collecting 

 at that time in that district would at once have treated our plants as exotic. 



It must be remembered, moreover, that when Banks and Solander, and 

 the Forsters, and Dr. Sparrman visited New Zealand, the cultivations of the 

 natives w~ere greatly more extensive than they are at present ; and it is 

 extremely improbable that neither in the numerous large tracts of cultivated 

 land nor in the vicinity of the many extensive pas which they visited, nor 

 along the many tracks which the natives then travelled, should specimens of a 

 plant possessing the habits of Polygonum aviculare have been found, if it then 

 existed at all as part of the indigenous flora of the islands. 



No doubt many indigenous plants have increased with extraordinary 

 rapidity of late years. I may instance for example the Chrysohactron hookeri, 

 which has spread and is still spreading over thousands of acres of moist 

 ground, on the higher part of the South Island pastoral country, owing to the 

 removal by fire of a vegetation which does not renew itself after fire, — such 

 as the sub-alpine species of DracophylluTn, Discaria, and Veronica — which in 

 mingled growth usually cover the terraces and mountain sides in such valleys 

 as those of the Acheron, the Clarence, the Upper Waiau, etc., in the Nelson 

 province. 



Even more remarkable is the extraordinary spread of Triticum scahrum 

 (blue-grass of the settlers) which over hundreds of thousands of acres of the 

 same class of country is gradually displacing the native grasses that first 

 follow the destruction of the sub-alpine growth. 



But none of these cases can be said to be strictly analogous to that of the 

 Polygonutn. In regard to each of the former certain checks have been 

 removed, and the plant is profiting by such removal. In the latter the plant 

 is always associated with the immediate occupation of land by man, making 

 its habitation either in places which he has disturbed and then sufiered to lie 

 waste, or along the sides of the tracks which he makes over virgin country. 



The spread of the Polygonum is more analogous to that of the plant 

 commonly termed the Maori cabbage. In every part of the South Island in 

 which we find any traces of native occupation or travel, even high amongst 



p 1 



