igiS. CoLGAN. — Alien Plants of Co. Dublin. B)y 



about two dozen of plants on Victoria Wharf, Kingstown, all in 191 7. 

 In the last station the plant was undoubtedly introduced with fodder 

 for army horses which was stacked here in large quantity during the 

 Easter week insurrection of 191 6. 



First noticed in Co. Dublin at East Wall, Dublin Harbour, in 1894. 



5. Columnae, jacq. 



2. One plant below the Windmill, Skerries, 191 3. 4, A few plants 

 by the roadside between Lucan and Woodlands, 1915. 8. Two plants 

 on Pigeon House road, 1907, and six plants in 1909 ; one plant by Pigeon 

 House gate, 191 3 ; thirty plants in Pembroke Park, 1907, and several 

 still there in 19 13. Two plants on the railway at Killiney station, 191 7. 



First noticed in Co. Dublin in association with the preceding species 

 in 1904. The ultimate establishment of both species in Co. DubUn seems 

 not unlikely. 



Lepidium ruderale, Linn. 



8, In July, 191 7, I found twenty-five fruiting plants of this species 

 in association with Sisymbrium pannonicum, Diplotaxis muralis, and 

 ■Linavia minor on the abandoned railway line near the Shanganagh River, 

 south of Killiney. 



An alien of rare appearance in Co. Dublin, as I can find no previous 

 record of more recent date than that for Kilbarrick in Flora Hihernica, 

 1836. 



L. perfoliatum, Linn. 



8, Seven fruiting plants found on the abandoned railway track south 

 of Killiney in July, 191 7, associated with the preceding species. 



This is the first Co. Dublin record for this plant, a native of south- 

 eastern Europe. It has been already recorded as a casual from Co. 

 Kildare, from Cork City, and from Belfast. 



Melilotus parviflora, Desi. 



7, About fifty plants found in 19 15 growing in association with 

 Matricaria discoidea on the footpath of a new road leading to Inchicore 

 brick-works. A native of south-eastern Europe here first recorded for 

 Co. Dublin. Previously recorded as a casual from Newry, Belfast, and 

 near Water ford. 



Matricaria discoidea. DC. 



The rapid spread of this American alien in Co. Dublin and in Ireland 

 since its first detection in 1894 offers a parallel amongst land plants to 

 the spread of the aquatic Elodea canadensis or Water Thyme. The 

 following is a selection from notes on its Dublin distribution made during 

 the interval 1910-1917 : — 2. About five dozens of plants on the Dorn, 

 Skerries, 1910, and about as many more in 191 2 in adjacent waste ground, 

 the site in the preceding year, of a travelling circus ; very abundant along 



