70 SUMMARY OF CURRENT RESEARCHES RELATING TO 



base upwards gradually increase in length to a maximum and then 

 diminish gradually. MacLeod limits his work to that part of the 

 stem which extends from the lowest leaf up to the longest one. This 

 part of the stem (as the number of leaves is very variable) he divides 

 into ten intervals, and measures the minimal, medium, and maximal 

 value of each character in the leaves of each interval. The measure- 

 ments of each given interval are thus made comparable with those of the 

 same interval in all the stems and species. The description of a species 

 according to the author's method consists of a number of tables giving 

 the gradation of each character. For each species he has recorded in a 

 series of tables the following characters : — Length, breadth, breadth at 

 the base, number of cells and breadth of the cells at the place of greatest 

 breadth, breadth of the border and number of cells of the border at the 

 same place, number of teeth at the border and on the nerve, length of 

 the nerve (reaching the summit or not), tooth at the summit of the leaf 

 (present or absent), total number of leaves of the fertile stem. For 

 purposes of identification he gives a series of tables showing the minimal 

 and maximal values of each character of the leaves of the tenth interval 

 (longest leaves), together with other characters. LTsually four of these 

 numerical characters suffice for the determination of a specimen, but 

 twelve to fifteen characters are available if necessary. 



Welsh Bryophyta.* — D. A. Jones gives an account of the mosses and 

 hepatics of the south-west of Anglesey, where he has succeeded in finding 

 several rare and interesting species. He describes the geology and 

 physical geography of Newliorough Sands, giving lists of the species 

 which characterize the different soil-formations, and an enumeration of 

 181 species of mosses and 55 hepatics. 



The same author t publishes an enumeration of the mosses and 

 hepatics of Denbighshire, prefaced by an account of the geology and 

 physical geography of the county, and of the moss-floras characteristic of 

 the various rocks ; and also of the injurious effects of the smoke of such 

 industrial centres as Ruabon and Wrexham upon vegetation. The 

 number of mosses recorded is 229, and of hepatics, 61. 



Wiltshire Mosses. | — C. P. Hurst gives an account of the' mosses of 

 East Wiltshire, collected mostly in Savernake Forest, and to the south- 

 east of it. The moss-flora of the sarsen stones is interesting ; these 

 siliceous rocks are found on chalk downs at Marlborough and Aldbourne, 

 and bear such interesting silicicolous species as Grimmia trichophylla, 

 G. suhsquarrosa, Hedwii/m ciliata, Orthotrkhum rvpestre, Ulota Hutchinsiae 

 — the first and last of which would probably be found no nearer than 

 on the granite rocks of Cornwall and South Wales ; and it has been 

 suggested that the spores have been carried thence by westerly winds. 

 In Savernake Forest fruiting specimens occur of certain specimens which 

 are usually sterile elsewhere. About 150 species are enumerated. 



* Lancashire and Cheshire Naturalist, Aug. 1917, pp. 111-51. 



t Naturalist, 1917, pp. 285-92, 321-7. 



: Wilts. Archseolog. & Nat. Hist. Mag., xxxix. (1917) pp. 449-55. 



