| 释义 |
mesarch, a.|ˈmɛzɑːk|
[f. meso- + Gr. ἀρχή beginning.]
1. Bot. [a. G. (H. zu Solms-Laubach Einleitung in die Paläophytologie (1887) xi. 263).] Of the development of the primary xylem, spreading in two or more directions from the earliest parts formed.
1891[see exarch a.]. 1902A. G. Tansley in Encycl. Brit. XXV. 414/2 (caption) Typical siphonostele (represented as mesarch) with internal phloem. 1954Biol. Rev. XXIX. 63 Such studies resulted in the recognition of the now well-known centripetal and centrifugal patterns of differentiation, the exarch, endarch, and mesarch types of xylem. 1965K. Esau Plant Anat. (ed. 2) xv. 378 In the third [type of xylem] the differentiation progresses in two or more directions from the first mature xylem elements. The resulting primary xylem is called mesarch.
2. Ecology. (See quot. 1923.)
1923G. E. Nichols in Ecology IV. 171 A third type [of succession] is here suggested, viz., mesarch... Mesarch series are those which originate in mesophytic habitats such as are afforded by moist, rich soils, and in which the vegetation likewise becomes progressively more and more advanced. 1960[see hydrarch a.]. |