1890-91.] Plant Multiplication. 417 



circulation. Moist warm weather greatly facilitates the miioii 

 of the bud with the stock. Layering consists in a branch or 

 shoot being bent into tlie soil and held in position by pegs : 

 there are several ways of performing the operation, the 

 principal being by twisting, by tonguing, by strangulation, 

 by ringing, and by circumposition. Inarching, sometimes 

 called grafting by approach, is also accomplished in various 

 ways, liut in every case both parts are nourished by their own 

 roots, and thus co-operate in forming a union. Root division 

 is another method of plant multiplication. I believe the 

 greater number of the plants of ipecacuanha now growing in 

 certain parts of India were originally propagated in this 

 manner by Mr Robert Lindsay, curator of the Royal Botanic 

 Garden, Edinburgh. The weeping willow (Scdix habylonica) 

 is distributed over a large area, both in the British Isles and 

 in North America, by its shoots or buds. Only the female 

 plant has yet been recognised. It is supposed that all the 

 individuals of this willow have originated from a single parent 

 tree. Some plants extend themselves by their own inherent 

 tendency to multiplication. I would refer in this connection 

 to that singular plant, Anacharis alsinastrum, which was 

 originally discovered in this country by tlie late Dr George 

 Johnston, of Berwick-on-Tweed, in the lake of Duns Castle 

 in 1842. It was again found by a lady botanist in 1849 in 

 a canal in Leicestershire. Later, it was noticed in other 

 localities, till now there is scarcely a stream or lake in the 

 country which is not infested with it. The plant is too well 

 known to need description. The male flowers were first 

 noticed by the late Mr Douglas in a pond on the Braid Hills, 

 in 1880, and were described by him in 'Science Gossip' for 

 that year; while Mr Tait Kinnear recorded their continued 

 flowering in the same locality in a note which will be 

 found in the first volume of this Society's ' Transactions.' ^ 

 Aquatic birds are frequently the involuntary agents in the 

 dissemination of water-plants, by carrying detached parts of 

 the plants from one part of the country to another attached 

 to their plumage or feet. The universality of the duckweed 

 {Lcmna riiinor), the smallest flowering-plant known, may be 

 thus accounted for. Wherever there is standing water, this 



1 See 'Trans. Edin. Nat. Field Club,' vol. i. p- 81- 



