| 释义 |
dryas Bot.|ˈdraɪæs|
[L.: see dryad. First used as a genus-name by Linnæus, Genera Plantarum (1737) 148.]
An evergreen sub-shrub of the genus so called, belonging to the family Rosaceæ and found in cold or alpine regions of the Northern Hemisphere. Cf. avens.
1798Smith & Sowerby Eng. Bot. VII. 451 We have cultivated the Dryas with success under a north wall. 1872Hogg & Johnson Wild Flowers Gt. Brit. VII. 556 Dryas Octopetala{ddd}Synonymes.—Dryas depressa,..White Dryas, English. 1927Glasgow Herald 26 Mar., A thin carpet of Arctic-Alpine vegetation such as a white-flowered dryas and dwarf-willows. 1936D. McCowan Animals of Canad. Rockies ii. 18 Dryas spreads its lovely floral carpet in the sun. 1955Times 4 July 10 That was Dryas, my dear fellow, for already your mountain avens is far back down the pass.
Restrict Bot. to sense 1 and add: 2. Geol. With capital initial. [after Sw. Dryaszonen (A. G. Nathorst Sveriges Geologi (1894) 292, 301).] Used attrib. to designate: (a) a type of clay in which dryas characteristically grows, associated with subarctic conditions; (b) each of a number of subarctic phases of the Late Glacial epoch in north-western Europe, characterized by the growth of dryas and other tundra vegetation (later also absol.).
[1910G. Andersson in Sveriges Geologiska Undersökning Årsbok III. i. 55 The underlying clay (at Stenstrup) bears a flora of the most northerly type we know from the late-glacial fresh-water strata (July temp. circa 6° C.) with Dryas and Salix polaris..as characteristic plants.] 1928K. Jessen in V. Nordmann Summary Geol. Denmark 133 We find at the bottom Dryas Clay, above that mud with macrophyllous birch, [etc.]. 1946F. E. Zeuner Dating Past iii. 61 The earlier part of the Subarctic phase is often called Dryas time, after a characteristic plant found in tundra-like environments. 1959Chambers's Encycl. V. 452/2 The earliest evidence of human settlement dates from the older Dryas period..and comprises summer camping-places of upper palaeolithic (Hamburgian) reindeer hunters. 1975J. G. Evans Environment Early Man Brit. Isles ii. 46 The solifluxion horizons are known as the Oldest Dryas.., the Older Dryas..and the Younger Dryas.., the name Dryas being taken from a characteristic plant of the Late-glacial, Dryas octopetala, the mountain avens. 1989Nature 15 June 532/2 The Younger Dryas was the last glacial cold spell. |