i9i8. CoLGAN. — Alien Plants of Co. Dublin. 89 



seedlings was discovered in a gravel pit near Robin Hood, Drimnagh, in 

 1916. 



A. Stelleriana, Besser. 



5. The North Bull station for this alien has of late years undergone a 

 great change due to the shifting of the sands by westerly gales. The ground 

 occupied by the plant in 1902, when it spread over a distance of a mile 

 and three-quarters, was a low, fiat shelf of sand a few feet above high tide 

 level and on the outside of the line of dunes which marks the eastern 

 limit of the Bull. In 19 14 a second line of dunes was found to have 

 drifted up on the seaward side of this shelf, running parallel with the 

 older line of dunes and forming with it a valley, from 8 to 10 feet deep, 

 stretching north and south for more than a third of a mile. A firing of 

 the Psamma in 1905 burnt up much of the Artemisia, and the shifting sands 

 buried large masses, so that in 1916 only a few plants were visible in this 

 sand dune trough or valley. In September, 1917, however, the plant 

 appeared in abundance towards the northern end of the dunes, emerging 

 from the drifted sands and sending up a single flowering stem. No doubt 

 many of the plants now missing from the earlier stations lie buried alive 

 and await only a further displacement of the loose sands to display once 

 more their broad cushions of silvery foliage. 



Senecio Cineraria, DC. 



8, This handsome Mediterranean alien is spreading rapidly by wind- 

 borne seeds southward along the sea cliffs of Killiney Bay, which it invaded 

 from a neighbouring garden about forty years ago. Its present extension 

 from Sorrento Point opposite Dalkey Island to its southern limit, the old 

 stone pier about 100 yards north of the ninth milestone on the railway 

 line, is fully one-third of a mile, and as the form of the coast continues 

 favourable for about an equal distance southward, the plant will pro- 

 bably in course of time double its present range. 



In addition to the cliffs running from Sorrento Point to near Vico 

 bathing-place, which for many years have been densely clad with the 

 plant, it has now become fully established to the southward in four of 

 the steep-walled coves formed by the jutting out of rocky capes. The 

 coast line here was carefully examined in February of the present year 

 with the following result : the first cove with its adjacent banks just 

 beyond the steps of the old bathing-place had about fifty large plants ; 

 the second, almost directly below Sunnyside on the Vico Road, 150 ; the 

 third, a little further south, sixty ; and the fourth, a little north of the 

 stone pier, ninety-five. Many of these were old plants, with numerous 

 stout recumbent stems forming masses of silvery-white foliage a yard in 

 diameter, and when grouped together on the cliffs conspicuous at half-a- 

 mile distance. 



The extension of range here detailed has been almost altogether effected 

 within the last ten years ; for in 1907 scarce half a dozen plants were 



