zonationn.

1898 Rep. 67th Meeting Brit. Assoc. Advancem. Sci. 1897 863 (heading) The zonal constitution and disposition of plant formations. By Frederic E. Clements.

1898 Rep. 67th Meeting Brit. Assoc. Advancem. Sci. 1897 863 The author has here reviewed the phytogeographical contributions bearing upon the subject in hand, with especial reference to the part they have played in the elaboration of the conception of zonation. In addition, he has endeavoured to demonstrate the fundamental universality of zonation in all divisions of the floral covering.

1904 F. E. Clements in Bot. Surv. Nebraska No. 7. 153 Zonation in a habitat... The line that connects the points of accumulated or abrupt change in the symmetry is a stress line or ecotone... Ecotones are well marked between formations, particularly where the medium changes: they are less distinct within formations. It is obvious that an ecotone separates two different series of zones in the one case, and merely two distinct zones in the other.

1926 A. G. Tansley & T. F. Chipp Aims & Methods Study Vegetation iv. 53 Adjacent plant communities are often arranged in more or less definite zones, following one another in constant order. This is specially noticeable in ascending a mountain (where it is called altitudinal zonation).

1936 J. Muir Geol. Tampico Region, Mexico 121 Reliable local zonation of both the Eocene and the Oligocene has been worked out in the Tampico area.

1969 Nature 15 Mar. 1005/2 Marine work during the first eight months concentrated on community structure and zonation on cliffs, reef flats and in mangrove woodland.

1971 Scot. Jrnl. Geol. 7 306 It is first necessary therefore to establish a regional metamorphic zonation.

1981 Birds Autumn 63/3 I would have preferred to have seen an accompanying annotated sketch so that the plant zonations could be easily recognised.

1899 Bot. Gaz. 28 237 There is a stage called zonation in which the nuclei, usually in metaphase, are lined up around the ooplasm.

1902 Bot. Gaz. Dec. 421 During the completion of the mitosis the ooplasm and periplasm become clearly differentiated, but as yet no plasmoderma exists. This process of differentiation has been termed zonation.

1975 Acta Anat. XCIII. 512 The zonation of the ooplasm reveals that a majority of the oocytes [of the teleost Schizothorax richardsonii] have a darkly stained inner and a lightly stained outer zone.