?s 



Elsee : ' Siciddens ' in Norih-East Yorkshire. 



facing the south, was surrounded by vegetation disposed as in 

 the following diagram : — 





X Pol ythichum 



Near the northern boundary there was much Polytrichum 

 and /uncus commtmis. with Call una and Bilberrj' appearing 

 sporadically. Towards the Bracken both /. communis and 

 the moss yielded to more Calluna. No Bracken occurred on 

 the Swidden, except at the S.W. corner. 



Another, in a similar situation, and with a somewhat 

 simildr disposition of plants around it, shewed the following 

 aspects : — Polyfrichuni dominated in the centre with a few 

 clumps oi Juncus communis towards the western edge ; Calluna 

 and Erica Teirali.w although very subordinate, were dispersed 

 amongst the moss, and at the extreme eastern edge there oc- 

 curred the Cotton Sedge [Eriophoriim vaginatnm) and Sphag- 

 num. Wherever the soil became drier, Polytrichum gave 

 place to Calluna with Juncus squarrosus. 



On wet Calhineta with Nardus stricta as an abundant 

 element in their flora, Swiddens present similar features to 

 the surrounding moors, except that Nardus becomes the chief 

 plant. This is probably owing to the fact that the stout tufts 

 and rootstocks of the grass withstand the iiring better than 

 Calluna, and consequently spring up again almost immediately. 

 Other species noted on such Swiddens are E. Tefralix, J. com- 

 munis and squarrosus, Potentilla. and Agrostis. 



Another example from the same type of moor shewed an 

 advance towards the Tetralix Moor. Nardus prevailed in one 

 part, and Erica Tetralix in another. Calluna and Potentilla 



Naturalist, 



