92 Floristik, Geographie, Systematik etc. 



in Yorkshire. The investigations were carried out at Huddersfield 

 previous to 1905, but the paper was completed at Zürich under 

 Prof. C. Schröter. 



Part I gives results of observations on the distribution of 

 dominant trees, the influence of various factors on the undergrowth 

 of woods, and the distribution of woodland plants beyond the limits 

 of existing woods. The studies were originally carried out on maps 

 (1 : 2500) which allowed great detail to be introduced ; it must 

 however be said that the reproduction of the maps is far beneath 

 the Standard which might be expected from the Linnean Society; 

 in most cases the maps have been rendered almost useless by 

 crowding them on to a small page as figures in the text. 



The first study is a typical mixed deciduous wood in the Goal 

 Measure area, and five maps show: n. distribution of trees (ßzY^ra^s, 

 Fagus, Ultnus montana, Acer pseiidoplatamis, Pinns sylvestris etc.); 

 b. distribution of Scilla festalis] c. distribution of Pteris aquilina; d. 

 distribution of grasses [Holcns rnollis and Deschampsia ßexuosa)\ 

 e. a soil map. Pterus occurs below the open canopy of Qiiercus and 

 Betida, but disappears below the shade-trees; it is not much 

 influenced by changes of soil. Scilla is found mainl}^ under open 

 canopy, but its distribution follows closely that of a deep soil 

 (loam with humus), and it avoids areas where the soil is cla}^ or 

 light sand. Holcus is dominant on the moister soils, Deschampsia 

 on the drier. The association of Scilla, Pteris, and Holcus is very 

 common in this district and is named a Meso-pteridetum; it is also 

 shown to be a „complementar}^ association", the aerial part of the 

 three dominant species being seasonally complementary, while the 

 sub-aerial parts are edaphically complementary since Holcus occupies 

 the surface soil, Pteris is intermediate, and Scilla is deepest. 



The same method is applied to a typical mixed deciduous wood 

 of the Millstone Grit area. Woods of this type occur on numerous 

 steep slopes in this district. The same trees are dominant and the 

 moister lower slopes are characterised by the meso-pteridetum. The 

 Upper slopes are drier, with a shallow soil and a superficial layer 

 of peat; Pteris is abundant but the associate plants are Calluna, 

 Vacciniiim Myrtillus, Holcus inollis and Deschampsia flexuosa, the 

 whole forming a xero-pteridetum; since the Pteris rhizomes in the 

 shallow soil are here found in the same layer as the Underground 

 parts of Calluna etc., the association is a competitive one. 



Two maps (badly reproduced) show the actual distribution of 

 trees and woodland plants of the undergrowth over an area of 66 

 Square miles. The undergrowth plants are seen to occupy a much 

 larger area than the trees and to attain a higher altitude. Remains 

 of Birch, etc. found in the moorland peat show that the former 

 Upper limit of forest was much above the altitude of the present 

 woodland. The associations on the deep peat of the moorland 

 plateau are also shown viz. Eriophorum vaginaturn, Vacciniutn 

 Myrtillus, Calluna. Pteris and grasses. 



Part IL The Influence of Environment on Structure. Several 

 plants shown in the previous part to occur in woods and out of 

 woods, and in both the mesophytic and xerophytic areas are here 

 compared anatomically. The author states that he has recorded the 

 modifications and noted the conditions of environment as far as 

 possible, but he is careful to point out direct adaptation may be 

 assumed too hastily, and he proposes to carr}^ out more detailed 

 observations on the environment. This part of the paper contains 



