DISTRIBUTION OF PLANTS IN BRITAIN* 70J 



little claim to be included iu the flora. Hence Mr. Watson dis- 

 tinguishes — 



1. Native species, apparently aboriginal, suoli as Corylus, Calluna, BeUis, 

 Teesdalla, 



2. Denizen species, doubtfully native, althougli maintaining their habitats 

 without the aid of man, as Aoonitum, Paeonia, Viola odorata, Impatiens noli-me- 

 tangere. 



3. Colonist species, or weeds occurring in cultivated land and about houses, 

 perhaps owing their presence to the operations of man, as Adonis, Papaver, 

 Githago. 



4. Alien species, originally introduced, although now more or less naturalised, 

 as Sempervivum, Mimulus, Hesperis, Camelina. 



5. Inoognitse, or species reputed British but requiring confirmation, as Ranun- 

 culus gramineus, GS-entiana acaulis, Tussilago alpina, Echinophora spinosa. 



According to the nature of the localities in which British plants 

 grow, they have been thus divided by Watson : — 



1. Pratal, plants of meadows or rich and damp grass lands, as Geranium 

 pratense. 



2. Pascual, plants of pastures and grassy commons, as Trifolium repens. 



3. Ericetal, plants of moors and heaths, as Calluna and Erica. 



4. Uliginal, plants of swamps and boggy ground, as Drosera and Pinguioula. 



5. Lacustral, immersed or floating plants, as Subularia aud Nymphsea. 



6. Paludal, plants of wet marshy ground^ as Typha. 



7. Inundatal, plants of places liable to be inundated in wet weather, as 

 Nasturtium terrestre. 



8. Viatical, plants of roadsides and rubbish heaps, as Lamium album and 

 Urtica dioica. 



9. Agrestal, plants of cultivated ground, as Papaver. 



10. Glareal, plants of dry exposed ground, chiefly gravel or sand, as Orni- 

 thopus and Sedum acre. 



11. Rupestral, rock and wall plants, as Cotyledon and Asplenium Euta- 

 muraria. 



12. Septal, hedge plants, as Bryony. 



13. Sylvestral, plants of woods, as Paris. " 



14. Littoral, plants of the sea-shore, as Statice and Convolvulus SoldaneUa. 



Taking a general view of the distribution of British flowering 

 plants and Ferns (excluding the Hibernian and Samian species), 

 Watson recognises the following types : — 



1. British type — species widely spread over Britain — found in aU or nearly all 

 the 18 provinces, and forming more than one-third of the British species, such as 

 Alnus glutinosa, Betula alba, Corylus Avellana, Salix capraea, Rosa cauina, Loni- 

 cera Periclymenum, Hedera Helix, Sarothamnus scoparius, Calluna vulgaris, 

 Ranunculus acris, Cerastium triviale, Potentilla TormentiUa, Trifolium repens, 

 Stellaria media, Lotus oomieulatus, Bellis perennis, Senecio vulgaris, Carduus. 

 palustris, Leontodon Taraxacum, Myosotis arvensis, PruneUa vulgaris, Plantago 

 lanceolata. Polygonum aviculare, Urtica dioiosi, Potamogeton natans, Lemna 

 minor, Juncus effusus, Carex panioea, Poa annua, Festuca ovina, Anthoxanthum 

 odoratum, Pteris aquilina, Polypodium vulgare, Lastrea Filix-mas. 



2. English type — species chiefly or exclusively found in England, and decreas- 

 ing in frequency northwards, constituting about l-5th of the whole flora, as 



