AFTER PROLONGED SUBMERSION IN THE SEA. 141 



that certain seeds do retain their vitality after submersion in the 

 sea, probably for a considerable period, they suggest also, as far 

 as these instances themselves are concerned, an explanation of the 

 mode in which the seeds may have passed from one locality to 

 another. The facts to which I refer are briefly these : — 



In the year 1843, the authorities of Poole in Dorsetshire deter- 

 mined to deepen the channels of Poole Harbour to facilitate navi- 

 gation. For this purpose a large number of ballast-lighter-barges 

 were employed to scrape the mud from the bottom of the channels 

 and convey it to the shore, where it was deposited in large quan- 

 tities. During the winter sufficient mud was thus obtained to 

 cover an area of some hundred square yards several feet in thick- 

 ness, and this was accumulated to such an extent, that a quay was 

 made of the hardened mud on the edge of the shore. 



The quay however was never used, nor its surface disturbed. 

 Early in the following spring I was surprised to see that the 

 surface of this harbour-mud exhibited abundant vegetation, of a 

 character totally distinct from that of the neighbouring shore ; and 

 as the season advanced, and the species were recognized, the flora 

 of this mud quay was not only found totally distinct from the 

 littoral vegetation which surrounded it, but it contained plants 

 which did not grow within many miles of the spot, and one which 

 was probably foreign to the county. Immediately surrounding 

 the mud quay was the ordinary vegetation of our southern harbour 

 shores, Statiee, Salicornia, Atriplecc, Carices, &c, whilst on this 

 exposed mud itself not one of them was to be seen ; but instead 

 of these there sprung up a large crop of oats and barley, some 

 plants of LysimacMa vulgaris, one plant of Centaurea calcitrapa, 

 and multitudes of Epilooium hirsutum ; and besides these there 

 were other plants which I did not recognize, or whose names I 

 have forgotten. 



To my mind it appeared conclusive, that the seeds which pro- 

 duced this crop of vegetation must have been in the mud at the 

 time it was deposited on the shore by the lighters. 



Taking the plants I have named as constituting part of the 

 vegetation of this new-made land, — they none of them grew in its 

 neighbourhood. The cereals, which constituted the most numerous 

 of the plants, were not cultivated within a mile of the spot. This 

 mud quay was made at the extremity of the peninsula upon which 

 the town of Poole is built, and the nearest field upon which cereals 

 are cultivated is on the other side of the 'town, and at least a mile 

 from the shore. 



