单词 | palmella |
释义 | palmellan. Biology. 1. Any of the unicellular green algae constituting (or formerly included in) the genus Palmella (family Tetrasporaceae or Palmellaceae), which divide to form colonies of non-motile cells embedded in mucilaginous masses; (in form Palmella) the genus itself. ΘΚΠ the world > plants > particular plants > algae > [noun] > green algae Codium1797 palmella1825 green alga1843 green water1854 chlorosperm1857 1825 Capt. Carmichael Let. in App. to Capt. Parry's Jrnl. Second Voy. iv. 429 You may safely arrange the Red Snow among the Palmellæ. 1869 F. P. Porcher Resources of Southern Fields (new ed.) 693 Three species of palmellæ, or palmelloid plants, one green, another red, a third lead color. 1910 Encycl. Brit. I. 595/2 Many Green Algae..are known to pass into a condition resembling that of a Palmella... It is, on the other hand, a danger..to conclude..that all irregular colonial forms, like Palmella, represent phases in the life of other Green Algae. 1992 E. G. Bellinger Key to Common Algae (ed. 4) 55 Palmella has cells which are spherical, spheroidal or rounded cylinders... Forms green to reddish gelatinous masses on damp substrates and vegetation. 2. A phase in the life cycle of various single-celled algae or unicellular flagellates during which they divide by fission to form colonies of non-motile cells within a mucilaginous matrix (formerly supposed to be species of Palmella: see sense 1); an organism in this stage of its life cycle; the colony thus formed. Frequently attributive, esp. in palmella stage [after German Palmellen-Zustand (L. Cienkowski 1876, in Bot. Zeitung 34 17)] . ΚΠ 1876 Jrnl. Bot., Brit. & Foreign 14 245 (heading) The Palmella-state of Stigeoclonium. 1909 A. Willey & S. J. Hickson in E. R. Lankester Treat. Zool. i. i. 156 It is difficult to distinguish this phase of life (the ‘palmella-stage’ as it is called) from a true plant under the terms of our definition. 1967 Oceanogr. & Marine Biol. 5 219 During the periods in which the medium is unfavourable..these palmella [sic] cease dividing. 1989 Encycl. Brit. V. 902/2 Some genera [of the protozoan order Heterochlorida] may be amoeboid during part of the life cycle; others may include a palmella stage. This is a new entry (OED Third Edition, March 2005; most recently modified version published online March 2022). < n.1825 |
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