Warming (1895) divided the plants, on the basis of their adaptation to water, into four major groups – hydrophytes, mesophytes, xerophytes and halophytes. A fifth group epiphytes can also be included.
# (i) Hydrophytes : The plants which grow in aquatic habitats are called hydrophytes. They are further grouped as –
(a) Submerged (e.g., Hydrilla)
(b) Attached floating (e.g., Nymphaea)
(c) Free-floating (e.g., Eichhornia, Wolffa)
(d) Amphibious or partly emerged hydrophytes (e.g., Sagittaria).
# (ii) Mesophytes : These are the plants which grow under moderate moisture and temperature conditions. They have no special adaptations to grow either in very dry or in very wet conditions (e.g., Sun flower, Brassica). These plants do not possess special adaptations to reduce transpiration.
# (iii) Xerophytes : The plants which grow in dry or xeric habitats (i.e., under deficient supply to available water) are called xerophytes. These plants face acute shortage of water and therefore, develop morphological, structural and physiological adaptations in order to survive under such habitats. The adaptations in plants are mainly to check the transpiration and survive under acute shortage of water. e.g., Cynodon (Doob grass), Casuarina, Euphorbia tirucalli, Asparagus, etc.
# (iv) Halophytes : Halophytes are those plants which grow in saline habitats, i.e., in salt marshes, alkaline soils, river estuaries, saline ponds near seashore or sandy and heavy soils having excess of salts. In such habitats, the water is present in sufficient amount but due to high osmotic concentrations it is physiologically not available to normal plants. Such conditions are said to be physiologically dry. e.g., Spartina, Atriplex, Portulaca etc.
# (v) Epiphytes : These are the plants which grow on other plants for space only. The plants are autotrophic and occur both in aquatic and terrestrial habitats. e.g., Vanda (an orchid).
Warming (1895) divided the plants, on the basis of their adaptation to water, into four major groups – hydrophytes, mesophytes, xerophytes and halophytes. A fifth group epiphytes can also be included.
# (i) Hydrophytes : The plants which grow in aquatic habitats are called hydrophytes. They are further grouped as –
(a) Submerged (e.g., Hydrilla)
(b) Attached floating (e.g., Nymphaea)
(c) Free-floating (e.g., Eichhornia, Wolffa)
(d) Amphibious or partly emerged hydrophytes (e.g., Sagittaria).
# (ii) Mesophytes : These are the plants which grow under moderate moisture and temperature conditions. They have no special adaptations to grow either in very dry or in very wet conditions (e.g., Sun flower, Brassica). These plants do not possess special adaptations to reduce transpiration.
# (iii) Xerophytes : The plants which grow in dry or xeric habitats (i.e., under deficient supply to available water) are called xerophytes. These plants face acute shortage of water and therefore, develop morphological, structural and physiological adaptations in order to survive under such habitats. The adaptations in plants are mainly to check the transpiration and survive under acute shortage of water. e.g., Cynodon (Doob grass), Casuarina, Euphorbia tirucalli, Asparagus, etc.
# (iv) Halophytes : Halophytes are those plants which grow in saline habitats, i.e., in salt marshes, alkaline soils, river estuaries, saline ponds near seashore or sandy and heavy soils having excess of salts. In such habitats, the water is present in sufficient amount but due to high osmotic concentrations it is physiologically not available to normal plants. Such conditions are said to be physiologically dry. e.g., Spartina, Atriplex, Portulaca etc.
# (v) Epiphytes : These are the plants which grow on other plants for space only. The plants are autotrophic and occur both in aquatic and terrestrial habitats. e.g., Vanda (an orchid).