Such terms as hydrophytes, xerophytes, and halophytes had been used by plant geographers before Warmings time e.g., by Schouw;4 and the terms evidently supply a want felt by botanists as they have come into general use.
The criticisms were directed chiefly to the inclusion of sand dune plants among halophytes, to the exclusion of halophytes from xerophytes, to the inclusion of bog xerophytes among hydrophytes, to the inclusion of all conifers among xerophytes and of all deciduous trees among mesophytes, and to the group of mesophytes in general.
A considerable proportion of halophytes are succulents, i.e.
Some halophytes tend - to lose their succulence when cultivated in a nonsaline soil; and some non-halophytes tend to become succulent when cultivated in a salty soil; there is, it need scarcely be stated, little or no evidence that such characters are transmitted.
Similarly, the small amount of cuticular and of epidermal protection, and of lignification in succulent halophytes may also be related to the same circumstance.