196 



HINTS AND NOTES 



Artemisia campestris, Veronica verna, V. tri- 

 phyllos, Muscari racemosum, Ornithogalum 

 umbellatutn, Carex ericetorutn. 



F. Arnold Lees, in a delightful old volume, 

 was one of the first to recognize the im- 

 portance of soils in determining the distribu- 

 tion of plants, and enumerates the following 

 among others as being especially confined to 

 sandy strata: Till&a muscosa, Turritis glabra, 

 Teesdalia nudicaulis, Silene anglica. Arenaria 

 peploides (maritime), A. (Spergularid) rubra, 

 Radiola millegrana, Erodium cicutarium, Tri- 

 folium suffocatum, Jasione montana, Centun- 

 culus minimus, Lamium amplexicaule, Scler- 

 anthus annuus, Phleum arenarium (maritime), 

 Festuca Myurus, Elymus arenarius, Carex 

 arenaria (the last two maritime). 



Sandy fields generally are characterized by 

 such plants as Little Bur Medick, Rough 

 Clover, Rigid Hare's Ear, French Cudweed, 

 Cut-leaved Speedwell, Biennial Knawel. The 

 connection between such tracts and rocks of a 

 sandy composition is shown by the occurrence 

 of plants common to both. Other plants found 

 here are Silky Wind Grass, Silvery Hair Grass, 

 Sand Fescue. 



Gravelly and Stony Places. Gravelly soil 

 is in general characteristic of heaths in the 

 north and west of England, but in the south 

 may be replaced by sand or clay. It is con- 

 nected in the first case with the formation of 

 moorpan, and trees will not grow on such 

 tracts; but the Pine grows, where the gravel 

 is not cemented together in this manner, on 

 gravelly heaths in East Anglia and elsewhere 

 in the south of England. 



Gravelly commons, as indicated by F. A. 

 Lees, have a characteristic flora, which is 

 common also to trap, serpentine, syenitic and 

 granitic rocks, including Trifolium repens, T. 

 fragiferunt, T. minus, T. filiforme, Omithopus 

 perpusillus, Plantago coronopus (also mari- 

 time). He points out that similar species 

 occur whatever be the age of the gravel, the 

 same plants occurring even to the Chamomile 

 (Anthemis nobilis) and Bupleurum tenuissi- 

 mum. And much depends on the relative 

 moisture or occurrence of pools. Here are 

 found Starwort, Forget-me-not, Bur Marigold 

 (liitit-ns cernua), and Pulicaria vulgaris, like the 

 Chamomile now very rare, and more or less 

 confined to commons in the south of Eng- 

 land. 



In marshy spots occur Ranunculus flammula, 

 R. hederaceus, Nasturtium terrestre, Carda- 

 mine hirsuta, Montia fontana, Peplis Portula, 

 Epilobium paJusIre, Helosciadium nodiflorum, 

 H. repens, Pedicularis sylvatica, Lvcopus euro- 

 PCPUS, Mentha hirsuta, M, piperifa, M. Pu- 

 legium (the two latter now very local or rare), 



Polygonum minus, BJysmus compressus, Heleo- 

 charis, Carices. 



Others on village greens and dry com- 

 mons are Polygonum aviculare, Nardzts stricta, 

 Chenopodium, Atriplex (in waste places), 

 Cerastium, Sagina, Filago, Polygala vulgaris, 

 Hypericum humifusum, Linum catharticum, 

 Potentilla anserina, P. tonnentilla, Carlina 

 vulgaris, Chrysanthemum inodonim (Matri- 

 caria inodora). Rampion, described here, is 

 also a characteristic plant of gravelly soil. 



Altitudes of Arctic-alpine or Boreal Plants. 

 The lowest limit of the arctic-alpine vegeta- 

 tion in Scotland is the 2coo-ft. contour, but in 

 Ireland and elsewhere it is not so high. It 

 is above the tree limit in this country. Ling 

 and Whortleberry, or moorland vegetation, 

 disappears, and a sort of grassland, with dwarf 

 vegetation, takes its place at higher levels, 

 made up of AJchemilla, Grasses (often vivi- 

 parous), Carex, Juncus, Luzula, Draba, Ceras- 

 tium, Potentilla, Saxifraga, Sedum. 



The types of plants are Scottish, or High- 

 land at higher altitudes, the latter chiefly in 

 Scotland. On Highland hills, e.g. on Ben 

 Muic Dhui (4300 ft.) the following occur: 

 Silene acaulis, Saxifraga stellaris, Salix her- 

 bacea (typically arctic), Luzula spicata, L. ar- 

 cuata, Carex rigida, Festuca ovina (viviparous 

 form). Elsewhere these plants occur on alpine 

 rocks in arctic and sub-arctic latitudes. 



The altitudes attained by some of these 

 arctic-alpine plants is illustrated by the follow- 

 ing list of plants on high mountain-tops, 

 many of which are rare or restricted to certain 

 localities, viz.: Draba rupestris (3000-3980 ft.), 

 Saxifraga cernua (3800 ft.), S. rivularis (3500- 

 3900 ft.), Arenaria rubella (2700-3800 ft.), 

 Sagina nivalis (3100-3900 ft.), Astragalus 

 alpinus, Oxytropis campestris, Erigeron al- 

 pinum (2500-3500 ft.), Gnaphalium norvegicum, 

 Menzesia ccerulea (2350-2460 ft.), Gentiana 

 nivalis (2400-3450 ft.), Myosotis pyrenaica 

 (2400-3450 ft.), Veronica fruticans (1200-3600 

 ft.), Salix arbuscula, S. lanata (dwarf willows), 

 Juncus biglumis, Carex alpina, C. rupestris, 

 C. atrofusca (2600 ft.) A number of lowland 

 types also occur at high altitudes (see ante). 

 In this group of arctic plants we see the influ- 

 ence of altitude and insolation in a marked 

 degree. 



Talus Slopes or Mountain -top Detritus. 

 The accumulation of talus slopes on sloping 

 hillsides forms a transition between bare rock 

 and rock with a thick layer of soil, the lime- 

 stone pavement, and sandy and gravelly soils, 

 being other transitions between them. 



In the case of arctic-alpine vegetation, dis- 

 integration owing to alternation of heat and 

 cold, landslips, erosion by water or by sand, 



