Habits and Habitats of Plants. 166 



7. Few British plants possess peltate leaves, i. e., leaves 

 circular in outline with the stem attached in the centre like the 

 handle of an umbrella. Such leaves are, however, possessed by 

 two small plants growing in damp places, both having creep- 

 ing stems and minute inconspicuous flowers, viz., the marsh 

 pennywort, Hydrocotyle vulfians (Nat. Order Umbelliferae), and 

 the Cornish moneywort, Sibthorpia europaa (Nat. Order Scrophu- 

 lariaceae). The long leaf- stalk carries up the leaf above the sur- 

 rounding vegetation, and the horizontally spreading blade ex- 

 poses a large surface to the light. A similar habit is possessed 

 by the ground ivy, Nepeta glechoma, belonging to the Labiatae, 

 which has leaves of circular outline, though not attached by the 

 centre to the stalk. 



8. Many plants growing in dry open pastures have a neat 

 dwarf habit of growth, with a rosette of broad spreading root- 

 leaves, a stem leafless or with few small leaves, and one or more 

 comparatively large flowers or heads of flowers. Familiar ex- 

 amples of this habit are the daisy, the plantains, and the mouse- 

 ear hawkweed ; but it is especially frequently met with in the 

 flora of mountain regions, as every one who has seen the flowers 

 of the higher Alps will remember. The habit seems to be an 

 adaptation to the circumstances of exposed situations, for it is 

 adopted in such situations by plants which in richer ground or 

 more sheltered places have tall branched leafy stems ; probably 

 by being spread out on the ground the leaves are protected from 

 injury by the wind. Other alpine plants have narrow leaves, 

 and grow in compact mossy tufts ; and this habit, again, is 

 common to plants of many different orders, e.g., Draba aizoides, 

 Silene acaulis, Cherleria sedoides, Androsace carnea, and several 

 species of Saxifraga. 



9. Succulent plants are not so prominent a feature of our 

 British flora as they are of those of hotter and drier climates, 

 where a fleshy habit is assumed by plants belonging to genera 

 which in this country are represented by weeds of common 

 character, such as Senecio and Euphorbia. Some of the tropical 

 Euphorbiae, indeed, exactly resemble Cacti. Our British succu- 

 lent plants mostly belong to the order Crassulacese, with occa- 

 sional representatives, chiefly maritime plants, in other orders, 

 especially the Chenopodiaceae. 



The advantage of a fleshy habit to plants growing in dry hot 

 situations is obvious, as it increases the volume of sap as com- 

 pared with the surface for evaporation, and thus enables them to 

 resist drying. Sedums put to dry in the press for the herbarium 

 will often grow between the sheets of blotting-paper. The fleshy 

 habit may similarly be useful to maritime plants in enabling 

 them to resist injury by the salt water ; but I am inclined to 

 regard it as due in some cases to the direct action of the salt 



