98 



Notes. 



August, 



to the ground, so closely that it appeared to cling to it. I tried thirty or 

 forty times with stones from half an ounce to a couple of pounds in weight, 

 and each time the butterfly dashed from its perch at the stone and whirled 

 down to the ground with it. Even when the stone passed the butterfly 

 at a distance of 12 feet the insect saw it coming and sprang at it. Assuming 

 that the movement was associated with the mating instinct, the butterfly 

 had certainly very liberal ideas as to the possible variation in size and 

 shape of other examples of its species. Had the passing object been an 

 insect-eating bird, it might have been rough on the Fritillary. 



R. Lloyd Praeger. 



Dublin. 



BOTANY. 



Acaena Sangfuisorbae an Alien Colonist. 



I am indebted to Miss Knowles for kind identification of a plant that 

 puzzled the members of the Dublin Naturalists' Field Club on their recent 

 excursion to Lucan, when it was seen growing profusely among the grass 

 and other herbage in a part of Captain Colthurst's demesne. It is Acaena 

 Sanguisorbae Vahl, the Burnet-leaved Sheep's Burr, a plant too familiar 

 to sheep farmers in Australia and New Zealand under the names " Bridgee- 

 widgee " and " Bidi-bidi," which are said to be corruptions of a Maori 

 name, " Piri-piri." 



Though probably a garden-escape at Lucan (like Artemisia Stelleriana 

 on the North Bull) this alien seems sufficiently strongly established to call 

 for a record in the " Irish Naturalist," especially when we learn that it has 

 already effected settlements in at least two districts in Great Britain — 

 on Dartmoor (this is the only locality given by S. T. Dunn in his " Alien 

 Flora of Britain," 1905) and on the banks of the Tweed (Hay ward and 

 Druce's " Adventive Flora of Tweedside," 19 19). The authors of both 

 the works just quoted (which were kindly looked up and shown to me by 

 Miss Knowles) believe the plant to have been carried alike to Dartmoor 

 and to Melrose by the power of its clinging seeds, but certain information 

 as to the mode of transport seems lacking in every case. 



The distinctive feature of this, otherwise very Burnet-like Australasian 

 plant is the conspicuous burr formed by the globose fruit-head when 

 flowering is over. Each calyx then develops two long sticky-tipped 

 spines (Miss Knowles tells me that she found one or two cases of three, but 

 two is certainly the usual number) ; and the burrs or " cuckens " (to give 

 them their local name, in full use at Lucan) thus formed are sufficiently 

 numerous and adhesive to explain readily why the plant is regarded as a 

 serious pest by sheep-farmers in its native country. Judged by their 

 tenacity in adhering to garments, I should say the burrs of Acaena Sanguis- 



