i88 



HINTS AND NOTES 



often associated with a bog, where there is 

 a resemblance to the moor formation. On the 

 other hand, heathland, as will be seen, often 

 passes into grassland. 



Dry and Wet Heaths. --Though heaths, as 

 a rule, are dry compared with moors or bogs, 

 they vary sufficiently to cause a difference in 

 the flora according as they are dry or wet, 

 relatively speaking. 



On the typically dry acid peaty soil, in the 

 lowlands of England especially, the dry heath 

 is characterized by the predominance of the 

 Heather or Ling, Hell Heather, and in some 

 parts by Cross -leaved Heath and Cornish 

 Heath. The Whortleberry is also a common 

 constituent. These plants form wide associa- 

 tions, and make up a large proportion of the 

 vegetation altogether. But with them may also 

 be found Milkwort, Pretty St. John's Wort, 

 Purging Flax, Broom, Furze, Tormentil, 

 Heath Bedstraw, Saw Wort, Harebell, Dod- 

 der, Red Rattle, Eyebright, Cow Wheat, 

 Wood Sage, Juniper, various Sedges (e.g. 

 Early Sedge), Bent Grasses, Matweed, Purple 

 Hair Grass, &c. 



The wet heath developed in hollows, where 

 water lies, may closely resemble the moor, and 

 the peat is then usually thicker. In such 

 places may be found Marsh Violet, Sundew, 

 Cranberry, Ling, Cross-leaved Heath, Butter- 

 wort, Lesser Skullcap, Gentian, Creeping 

 Willow, Sweet Gale, Bog Orchid, Heath 

 Rush, Spike Rushes, Bulrush, Cotton Grass, 

 Beak Sedge, Flea Sedge, Purple Hair Grass, 

 Matweed, Royal Fern, Club Moss, and Bog 

 Mosses. 



Ericaceous Plants and Heaths. One of the 

 chief characteristics of the heath is the pre- 

 dominance of the plant which gives its name 

 to this type of formation. Such plants as Ling, 

 Bell Heather, Cross-leaved Heath, Ciliate 

 Heath, Cornish Heath, Mediterranean Heath, 

 all have the characteristic Heath habit. They 

 are all adapted to resist the effects of drought, 

 to which heaths, especially on stony or gravelly 

 soils, are much subject. 



In some cases Ling itself is the principal 

 plant ; on damper soils the Cross-leaved 

 Heath may take its place, or the Whortle- 

 berry, which is also adapted to dry-soil con- 

 ditions. The dominance of the Heath plants 

 excludes all but a few plants that in the 

 main have the grass habit, and so can exist 

 side by side with the Heaths, and main- 

 tain their struggle successfully where others 

 would be crowded out. Where there are a 

 good number of other species present, the 

 heath merges into a grass heath. One reason 

 for the dominance of the heath plants is the 

 periodic burning of Ling and Heath each 



spring to encourage the growth of new shoots, 

 largely done where grouse are preserved. This 

 destroys the other plants. A few, however, 

 recover, even before tin- Ling, as Whortle- 

 berry, Sheep's Fescue, Matweed, Cotton ( .. 

 &c. 



Distribution of Heaths.- The heaths of the 

 British Islands occupy certain well -dt -lim-d 

 areas, where there is a considerable rainfall, on 

 more or less sandy or gravelly soils. Thus they 

 occur in the south and west of England, and in 

 Scotland, and in the Midlands, and elsewhere 

 on a lesser scale. The rainfall in Scotland, 

 which may amount to 40 or more inches of 

 rain annually, exceeds that in the English 

 areas named by at least 15 in. 



The heaths of the Eastern Counties have not 

 more than 25 in. of rain per annum, and peat 

 is not formed to any great extent. In the 

 south of England it is much less. In Norfolk 

 and Suffolk the Ling-covered areas may be 

 transitional to grass heath, and also develop 

 the flora of the chalk pasture. 



In the Cornish area the Cornish Heath, 

 Dwarf Furze, Ciliate Heath are characteristic. 

 In the Midlands the heaths are ill developed. 

 Yorkshire has great regions of heather, called 

 moors. There is 35 in. of rain per annum, 

 and both wet and dry heaths occur. 



Degenerate Woods and Heaths. From the' 

 frequent association of certain tree associations 

 with heaths, it is probable that in some cases, 

 at any rate, the heath is a degenerate type of 

 woodland, as where Oak, Birch, and Pine 

 occur, and form a scrub with heath plants. 

 But in many cases, especially on coarse sand- 

 stones and sands, the heath was itself origin- 

 ally developed. 



In any case, when a heath occurs it trans- 

 forms the soil characteristics, for a layer of peat 

 is formed, which at once affords a home for cer- 

 tain types of plants, and excludes others that 

 cannot grow in humus. It has been found on 

 the Continent that the cause of the degenera- 

 tion of woodland into heath is due to the leach- 

 ing out of the sand from the soil. It is pro- 

 bable that in the same way the leaching out of 

 humus from a soil originally rich in this has 

 been responsible for the disappearance from 

 certain districts of such humus-loving plants as 

 Dog's Mercury and Lords and Ladies. In 

 place of the mild humus of a woodland re- 

 quired by such plants, an acid humus is formed 

 suitable for heath types. The consolidation of 

 sandy, gravelly soil by humus acids similarly 

 affects the growth of trees, and renders the 

 persistence of woodland impossible and the for- 

 mation of heaths possible. 



Grass Heath. Where the soil is sandy there 

 are frequently wide tracts of uniform so-called 



