FLOWERLESS PLANTS, AND THEIR HABITATS. 



(Concluded.) 



ByH. Franklin Parsons, M.D., F.G.S. 



The traveller wlio is gifted with an observing eye must have noticed 

 the great difference between different parts of England as regards 

 the abundance and luxuriance of cryptogamic vegetation. In some 

 districts, especially near the western coasts, as Devonshire and the 

 Lake district, every tree trunk, stone, and bank is covered with a rich 

 drapery of green moss and hoary lichen, giving a softness and charm 

 to the scenery, which in other districts, as our own, is lacking. In 

 the eastern counties — and still more, in the smoke-blackened vicinity 

 of manufacturing towns, — the tree trunks are bare, and the mosses 

 that occur are mostly terrestrial kinds. In travelling up to London 

 from the west, I have noticed that the moss-covered trees disappear 

 from the scenery somewhere about the borders of Wiltshire and Berk- 

 shire. It does not necessarily follow that such districts are actually 

 deficient in species ; for instance, in our own Goole district I have 

 found 130 species of mosses, which is as many as I found in North 

 Somerset, where I formerly lived, although mosses were incomparably 

 more abundant and luxuriant there than here. In the following 

 remarks I shall take the abundance, luxuriance, and fertility of 

 individuals, rather than the number of species met with, as the test 

 by which to judge whether a given locality be favourable to crypto- 

 gamic vegetation or otherwise. Among the cryptogams, the more 

 luxuriant the individual, the more likely it is as a rule to produce 

 fruit ; in the flowering plants, on the contrary, the functions of 

 nutrition and reproduction are to some extent antagonistic. 



Tree trunks appear to me to give the best criterion by which to 

 judge whether the climate of a given district is favourable to crypto- 

 gams or otherwise, as such stations eliminate the influence of the 

 composition and drainage of the soil, &c. All trees are not equally 

 affected by mosses ; the ash is by far the favourite, and the Goole 

 district would be much worse off for mosses than it is, were it not 

 that the ash is the prevailing tree. Indeed a district like ours, where 

 mosses do not grow readily, serves to show their likes and dislikes 

 better than one where they will grow anywhere. The stumps and 

 trunks of hazel and hawthorn in hedgerows are also favourite situa- 

 tions. They are always found most luxuriant on the weather side of 

 the tree. 



N. S., Vol. IV., Nov., 1878. 



