196 



HINTS AND NOTES 



Artemisia campcslris, I'eronica vema, J'. Iri- 

 phyllos, Muscari racemosum, Oniithoffalum 

 umbellalum, Carex ericetonim. 



F. Arnold Lees, in a dt-lig'litful old volunio, 

 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: Tillcea muscosa, Turritis glabra^ 

 TccsdaJia nudicaulis, Sileiw aiijflica. Airitaria 

 pcpluides (maritime), A. {Sfli'rQ-ii/aricj) itibrn, 

 A'ljiiio/u jiiilhi^rana, Erodiiim cicularium, Tri- 

 foliiim suffocatum, Jasionc montana, Ccntiin- 

 culus iiiiniinus, I.amium amplexicaulc, Sder- 

 anthus aniiuus, Phleiim arennrium (maritime), 

 I-'estuca Myurus, Elytmis arcnarius, Carcx 

 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 

 mav 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. \. 

 Lees, have a characteristic flora, which is 

 common also to trap, serpentine, syenitic and 

 granitic rocks, including Trifolium rcpens, T. 

 frag-iferum, T. minus, T. filijorme, Ornithopus 

 perpiisiHiis, Pianftigo coivnopus (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 tiobi/is) and Buplcurum tenuissi- 

 mitm. .And much depends on the relative 

 moisture or occurrence of pools. Here are 

 found Starwort, Forget-me-not, Bur Marigold 

 (Bidens cernua), and Pitlicaria vuli^aris^ like tlie 

 Chamomile now very rare, and more or less 

 confined to commons in the south of Eng- 

 land. 



In marshy spots occwr Ranunculus flammiila, 

 R. hederaceus, Nasturtittm tcrrcstre, Carda- 

 mine hirsuta, Montia foulann, Peplis Pofiula, 

 Epilohium palusire, Hflosciadium nodijioriiin, 

 II. rcpL-ns, I'i'dicularis srlvntica, Lycopus eiiro- 

 ptFus, Mentha hirsuta, M. piperita, M. Pu- 

 legiu7n (the two latter now very local or rare). 



Polygonum minus, Blysmus compressus, Ileleo- 

 (haris, Carices. 



Others on village greens and dry com- 

 mons -.we. Polygonum aviculare, A'ardus stricta, 

 Chcnopodium, Alriplex (in waste places), 

 Cerastium, Sagina, Filago, Polygala 7'ulgaris, 

 Hypericum humifusum, Linum catharlicum, 

 Potentilla anseriua, P. tormentilla, Carlina 

 vulgaris. Chrysanthemum inodorum (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 2000-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 liigher levels, 

 made up of Alchemilla, Grasses (often vivi- 

 parous), Carex, Juncus, Lunula, Draha, Ceras- 

 tium, Potentilla, Saxifraga, Sedum. 



The types of plants arc 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- 

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

 cuata, Carex rigida, Fcstuca ovina (\i\ iparous 

 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.: Draha rupestris (3000-3980 ft.), 

 Saxifraga cernua (3800 ft.), 5^. rivularis (3500- 

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

 Sagina nivalis (3100-3900 ft.). Astragalus 

 alpinus, Oxytropis eampestris, Krigerou al- 

 pinum (2500-3500 ft.), Gnaphalium nur-eegicum, 

 Men::esia ca'rulca (2350-2460 ft.), Gentiana 

 ?iivalis (2400-3450 ft.), Myosotis pyrenaica 

 (2400-3450 ft.), J'eronica frutieans (1200-3600 

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

 /uncus biglumis, Carex alpina, C. rupestris, 

 C. atrofnsca (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 he.at and 

 cold, landslips, erosion by water or by sand. 



