Clare Island Survey — PJiancrogamia. 10 41 



large size in comparison with the present tree-vegetation, occur abundantly 

 in the peat in some places ; but these belong to an earlier epoch, and there 

 are no indications that they were destroyed by man. 



It is on the farm-land area that the flora has been most profoundly 

 altered, the operations consisting mainly of drainage and tillage. The ground 

 is wet almost everywhere, on account of the high rainfall and perennial 

 dampness of the air, and is usually peaty. The drainage of the land is very 

 primitive. Deep ditches have been dug in places along the edges of the 

 fields, and the material thrown up into high banks to give shelter. Over the 

 whole area of the fields parallel open trenches are dug, running with the 

 slope. These are about 6 feet to 10 feet apart, 2 feet to 3 feet wide, and 1 foot 

 to 3 feet deep. The material is thrown on the intervening ridges, and on 

 these " lazy beds " the crop is sown or planted. Wherever cultivation has 

 been practised, even at a remote time, the marks of these trenches and ridges 

 remain, giving the land a fluted appearance, and showing the high-tide mark 

 of tillage, which occurred before the dreadful famine year of 1846. Covered 

 drains were unknown on the island until a couple of years ago, and are still 

 looked on as a doubtful experiment. Loose stone walls are also built, to clear 

 the land and to give shelter. The result of all these operations is to diminish 

 the proportion of marsh plants, and to increase the mesophile vegetation. The 

 better drainage and shelter given by the ditches, banks, and walls, have, I 

 think, considerably increased the quantity of Bracken and of Brambles, for 

 instance. 



The usual crops are potatoes and oats, with some barley, rye, turnips, 

 mangels, and cabbages. The weed flora is poor in variety. Among the 

 cereals Brassica Papa var. Briggsii is the most conspicuous and abundant 

 colonist ; B. alba is the next commonest Brassica ; B. Sinapis is a rather 

 bad third. Other prevailing crop-weeds are Spergida arvensis, Polygonum 

 Persicaria, P. Hydropiper, and Euphorbia Helioscopia. Poppies, Valerian- 

 ellas, &c, are absent ; Fumitories very rare. The human activity of the 

 island centres about the harbour, in the extreme south-east, and the cliapel, 

 on the southern shore a couple of miles away.. Around these spots are 

 grouped such species as Sisymbrium officinale, Trifolium dubium, Calystegia 

 sepium, Veronica polita, V. agrestis, V. Tournefortii, Lamium hybridum, 

 L. intermedium, Stachys arvensis, Polygonum Convolvidus, all of which must 

 on Clare Island rank as introduced plants. 



When land is left uncultivated, it is rapidly invaded by the native flora ; 

 annual species disappear, and indigenous perennials soon form a closed 

 vegetation ; on the lower grounds, grasses become dominant, on the upper 

 grounds Calluna. A few examples of stages of this regeneration may be given. 



B.I.A. PROC, VOL. XXXI, F 10 



