44 BOTANY. 



buildings. Some of these seem to select the habitations of man and animals, 

 on account of certain nitrogenous and inorganic matters Avhich enter into 

 their composition. Among them may be noticed Nettles, Pellitory, Docks, 

 Borage, Henbane, Xanthiam. Here also have been placed some plants 

 immediately connected with the habitation of man, such as Racodiiim cellaj'e, 

 a fungus found on wine casks ; Conferva fenestralis, an alga produced on 

 window-panes ; and Conferva dendrita, one developed on paper. Some 

 plants, as Seniperviam tecfornm, select the roofs of houses. 



11. Plants growing- in Vegetable Mould, such as bog plants, or those 

 growing on wet soil, so soft that it yields to the foot, but rises again ; and 

 marsh plants, growing in wet soil, which sinks under the foot and does not 

 rise. To the former class belong such plants as Pinguicula alpina and 

 Prhmda farinosa ; to the latter, such as Menyanthes, Comarum, Bidens 

 cernua. 



12. Forest Plants, including trees which live in society, as the Oak, the 

 Beech, Firs, &c., and the plants which grow under their shelter, as the 

 greater part of the European Orchises, some species of Carex and Orobanche. 

 Some plants especially grow in pine and fir-woods, as LinnfBa horealis and 

 some Pyrolas. 



13. Plants of Sterile Places, found in barren rocks, by road-sides. This 

 is a heterogeneous class, and contains many plants of uncertain character. 

 Under it are included the plants of uncultivated grounds, as those found on 

 moors, where Calluna vulgaris, common heath, and various Heaths, Juniper, 

 Andromeda, and some species of Polytrichum occur. 



14. Plants of the thickets or hedges, comprehending the small shrubs 

 Avhich constitute the hedge or thicket, as the Hawthorn and Sweet-brier : 

 and the herbaceous plants which grow at the foot of these shrubs, as Adoxa, 

 Wood Sorrel, Violets ; and those which climb among their numerous branches, 

 as Bryony, Black Bryony, Honeysuckle, Traveller's Joy, and some species of 

 Lathyrns. 



15. Plants of the Mountains, which De Candolle proposes to divide into 

 two sections : 1. Those which grow on Alpine mountains, the summits of 

 which are covered with perpetual snow, and where, during the heat of summer, 

 there is a continual and abundant flow of moisture, as numerous Saxi- 

 frages, Gentians, Primroses, and Rhododendrons. 2. Those inhabiting moun- 

 tains on which the snow disappears during summer, as several species 

 of Snap-dragon, among others the Alpine Snap-dragon. Umbelliferous 

 plants, chiefly belonging to the genus Sesseli, meadow Saxifrage, Labiate 

 plants, «fee. 



C. Plants Growing in Special Localities. 



16. Parasitic Plants, which derive their nourishment from other vegeta- 

 bles, and which, consequently, may be found in all the preceding situations ; as 

 the Mistletoe, species of Orobanche, Cuscuta (Dodder), Loranthus, Rafflesia, 

 and numerous Fungi. 



17. Pseudo-parasitic Plants, or Epiphytes, which live upon dead 

 44 



