Three words for the price of one this time: xeric, hydric and mesic. Something xeric is very dry. It’s a term in ecology and might be applied, for example, to a bare rock exposed to the sun. It was formed from classical Greek xerōs, dry (also the source of Xerox, a method of dry copying), as a comparatively modern creation:
We offer the terms ‘xeric’, ‘hydric’ and ‘mesic’, to be defined as follows: Xeric (hydric, mesic): characterized by or pertaining to conditions of scanty (abundant, medium) moisture supply.
A Suggestion to Amend Certain Familiar Ecological Terms, by W S Cooper and A O Weese, in Ecology, 1926. Both authors were pioneering ecologists, in a period in which the term was hardly known to the general public. The Ecological Society of America commemorates one of the authors in its annual William Skinner Cooper award.
Until then, the only word available was xerophytic, which strictly could be used solely of plants (because of the ending -phytic, from Greek phuton, a plant) that were adapted to dry habitats. Messrs Cooper and Weese wanted a term to describe habitats in general.
The second word they invented, hydric (from Greek hudōr, water), of a habitat that has a plentiful supply of water, was potentially confusing, since it already existed as a term in chemistry for hydrogen in chemical combination. And mesic (from Greek mesos, middle), for a habitat having an intermediate supply of water, has since been independently recreated by atomic physicists to refer to the subatomic particle called the meson. But in practice ambiguity in either case is unlikely.
These days, though xeric is hardly an everyday word, serious gardeners will know it in connection with dry landscaping or xeriscaping:
Instead of seeing the park as half empty, he saw the opportunity to design drought-tolerant gardens to promote the benefits of planting native and xeric plants.
The Denver Post, 21 May 2010.