Elgee : ' Sividdens ' in North-East Yorkshire. yg 



were of not infrequent occurrence, whilst a species of Carex 

 was sporadic. 



Sometimes Swidclens on wet moors are clothed with 

 nothing else but E. Tetralix. On Harland Moor, near Gillamoor, 

 this species prevailed on an old Swidden. Calluna was generally 

 absent, but interspersed amongst the Heath were patches of 

 Nardus and /. squarrosus. In a wetter part, E. Tetralix, though 

 still the dominant plant, was much mixed with Calluna and 

 the Flying Bent [Molinia varia). The surrounding moor was 

 mostly Heather. Such Tetralix Moors are of rare occurrence 

 on other than burnt areas. The most extensive natural 

 Tetralix Moor in North East Yorkshire is that of May Moss, 

 near Goathland. 



A yet more remarkable example of the influence of burning 

 has to be named. Many of the moorland slopes have at one 

 period been wooded, and these woods have been removed by 

 either natural or artificial means. Bracken and Heather have 

 covered their sites so that nearly all trace of the original wood- 

 land has been lost. These slopes, as previously mentioned, 

 are then burnt, and on a .wet Swidden with a southerly slope 

 the following plant association radically distinct from that of 

 the surrounding moor was observed. 



The dominant plants were Molinia varia in wet places and 

 Calluna in the drier. Numerous species were Scirpus caespitosa 

 and /. communis ; the principal species of sporadic occurrence 

 were /. squarrosus, Potentilla, E. Tetralix, Luzula campestris, 

 V. Myrtillus, Aira flexiiosa, Holcus mollis, and Polytrichum. 

 A small quantity of Sphagnum occurred- associated with 

 Drosera rotundifolia. Vaccinium Vitis-idaea was also seen in 

 one place. Part of the original wood remains, consisting of a 

 few shrubs of Salix and Alder, with an undergrowth of Molinia 

 and Rubus. It seems probable that in this case. Molinia was 

 a constituent of the woodland undergrowth which must have 

 contained various other ericetal plants. I have frequently 

 seen Molinia flourishing on damp ground under Birch in the 

 vicinity of the moors. ■ 



Finally it may be remarked that if Cotton Grass moors are 

 burnt, the sedge is the first plant to reclothe the Swiddens with 

 ts characteristic tussocks. This is due to the resistance which 

 its stout growth offers to the burning. 



It is significant to note that in the vast majoritj' of cases 

 ericetal plants alone spring up on the Swiddens. So far as my 



1910 Feb. I. 



