1 9 o 



HINTS AND NOTES 



place, the absence of shade causes the plants 

 to adapt themselves to dry conditions. The 

 leases are leathery, rigid, narrow or linear, 

 the margins inrolled, and the plants are often 

 hairy. The exposure of heath plants to the 

 wind is also a characteristic feature, and they 

 have a typical habit correlated with this 

 factor. 



The open heath again lends itself to the 

 successful pollination of the chief ericaceous 

 types by insects. In the case of grass heath, 

 on the other hand, the dominant Grasses are 

 enabled to disperse their pollen, and later 

 their seed, by the aid of the wind. 



Dry-soil Types. The heath flora is especially 

 exposed to dry-soil conditions. The conditions 

 upon a heath further involve dry air, intense 

 illumination, heat, and wind exposure. As a 

 consequence, heath plants display very marked 

 xerophytic adaptations. 



Extensiveness of Heath Plants. A special 

 feature of heaths is the well-marked continuity 

 of the association of such dominant plants as 

 Furze, Broom, Ling, Heath, Whortleberry, 

 &c. This is partly due to the uniformity of 

 the conditions. The heath is developed upon 

 a particular kind of soil, hence it is natural 

 that certain plant types, as Ling, &c. , are char- 

 acteristic of such a soil. Heath is a stable 

 association, and as such not liable to invasion 

 by or migration into other types. 



Where Ericaceous types cover wide areas, 

 other plants cannot grow, or become dwarfed. 

 If the formation is open, however, grass heath 

 develops, and the grass type becomes equally 

 prevalent or even entirely dominant. 



Game and Moors and Heaths. An interest- 

 ing feature of the moorlands and the heaths 

 is the close association between gamebirds and 

 Kricaceous types of plants. It is the game- 

 birds, of course, that are dependent, and there 

 is no reason to think that Ericaceous plants 

 are in any way dependent upon the agency of 

 game for their dominance, unless it be that 

 in modern times the popularity of sport has 

 tended to conserve heaths and moors as the 

 special habitat of game. 



Upland Heaths and Lowland Heaths. As 

 intimated in Section XII, there are two alti- 

 tudes at which Ling and Heath, or the chief 

 components of a heath, occur. Though these 

 two levels are not uniform, they serve to indi- 

 cate the particular zones at which the heaths 

 in different areas are found. 



The English heaths of the South of England 

 and the East Counties are more or less of the 

 lowland type, and the same may be said of the 

 Irish heaths, excluding the west coast moors 

 and heaths. Of this type are Exmoor, Dart- 

 moor, and numerous heath -clad commons. 



Such heaths normally occur between 300 and 

 500 ft. above sea-level, but many of them come 

 right down to the sea. 



The upland heaths are developed in the 

 hilliest parts of the country in the west, Wales, 

 Gloucestershire, the Pennines, Lake District, 

 Yorkshire, Scotland. They go by the name 

 of moors in many districts, especially in York- 

 shire. The height to which Calluna and 

 Erica extend, respectively, differs, and upon 

 this fact zones have been based. Ling ascends 

 the highest (2000 ft.), and the Cross-leaved 

 Heath next, Purple Heath the least of the 

 three. 



Transition to Pasture. The similarity between 

 the true heath and the grass heath suggests 

 that a heath may ultimately pass into pasture. 

 Heaths may, in fact, at their margin, grade ' 

 into dry pastures without Ling or other heath 

 plants. This is merely the illustration of a 

 natural law of succession. The transition of 

 heath into pasture in this manner, however, 

 must not be confused with the existence of 

 vestiges of true heath or grass heath amongst 

 neutral grassland, for in this case cultivation 

 has been the determining factor. It is true 

 that the result is largely the same, but the 

 originating cause (and process) is dissimilar. 

 This fact may be illustrated by the study of 

 a heath locally and its marginal transition to 

 pasture or grass heath, and the comparison 

 between this type and the possible representa' 

 tion of a vestigial heath in the same area. 



In the transition from heath to pasture it 

 is interesting to note the elimination of the 

 Ericaceous dry-soil types, and the persistence 

 or appearance of ordinary meadow types. 

 Once the Ling and Heath, or Furze, or Oak, 

 or Pine are removed, a new flora comes into 

 existence. The transition from grass heath 

 which thus results is very easy, into a normal, 

 dry pasture. Indeed, many dry pastures may 

 be found to retain a few traces of their former 

 condition, including some dry-soil types, as 

 Mountain Everlasting, &c. By drainage, the 

 wet-heath types also disappear, and there may 

 then be little left to indicate the former char- 

 acter of the vegetation. 



The Habitats of Heath Plants. Owing to 

 the uniform type of soil, rich in acid humus, 

 demanded, heath plants as a whole exhibit a 

 marked similarity in their choice of habitat. 

 In this connection must be considered the 

 relation between the true heath, grass heath, 

 and pasture, on the one hand, and the moister 

 types of habitat of the wet heath, moor, and 

 bog on the other. 



There are thus dry habitats and wet habi- 

 tats, depending upon the altitude to some ex- 

 tent. Wet heaths may also be developed upon 



