xxi v] WATER-FOWL AND WATER PLANTS 301 



on their suddenly emerging from the water. Guppy 1 found that 

 a week in sea water killed the seeds of Lemna minor, while a day 

 generally killed the fronds, but he considers that in damp 

 weather the plants might, for a day or two, withstand exposure 

 to the atmosphere and thus might be carried a few hundred 

 miles entangled in a bird's plumage a supposition to which the 

 observations of Weddell and Darwin lend colour. 



That seeds and fruits may be conveyed in mud, adhering to 

 the beaks, feet, or feathers of birds, has long been known. Most 

 of the records on this point relate to plants which are not strictly 

 aquatic, but Kerner 2 mentions Elatine hydropiper, Glyceria 

 fluitam and Limosella aquatica among the species which he has 

 himself found in this situation. Duval-Jouve 3 , who also paid 

 attention to this subject, observed at different times the debris 

 of twelve plant species adhering to the feet and breasts of the 

 migrating web-footed birds exposed for sale in a market. 



Our knowledge of the internal conveyance by birds of the 

 seeds of aquatics, rests almost entirely on the work of Guppy 4 , 

 whose remarkable observations on the life-histories of water 

 plants have been frequently cited in the foregoing chapters. 

 Guppy dissected and examined thirteen wild Ducks purchased 

 in the London markets, and found altogether 828 seeds 

 and fruits, including those of Sparganium and Potamogeton. 

 Seeds obtained from this source sprouted with such greatly 

 increased rapidity that Guppy describes the wild Ducks 

 as "flying germinators." He adds the observation that, of a 

 large number of nutlets of Potamogeton natans which were eaten 

 and passed by a domestic Duck in December, 60 per cent, 

 germinated in the following spring, whereas, at the same date, 

 sprouting had only occurred in the case of i per cent, of the 

 nutlets left over in the vessel from which the Duck had been fed. 



It is possible that, in certain cases, the seeds of water plants 



1 Guppy, H. B. (1893). 



2 Kerner, A. and Oliver, F. W. (1894-1895). 



3 Duval-Jouve, J. (1864). 



4 Guppy, H. B. (1894 1 ), (1897) and (1906). 



