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An order of algae in the division Chlorophyta in which the thalli are macroscopic, attached tubes or sheets.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an order of green algae. The thallus is lamellate (consisting of one or two layers of cells), tubular or saclike (consisting of a single layer of cells), or filamentous (consisting of two rows of cells). The cells are mononuclear, and the chloroplasts are lamellate and have pyrenoids. Vegetative reproduction is achieved with parts of the thallus; asexual reproduction is by means of zoospores having two or four flagella. The sexual process is iso-gamy or heterogamy. The zygote appears without a resting period, and meiosis occurs with the formation of the zoospores. The sporophyte and gametophyte have the same structure, or one may be multicellular or unicellular but considerably smaller than the other. Sometimes one of the forms is omitted from the developmental cycle.

The algae grow in seas and, less commonly, in brackish and fresh waters. Some species of the genera Viva, Monostroma, and Enteromorpha are used as food. Monostroma are cultivated in Japan.

The Russian common name for the order Ulvales is also used to designate a family of that order, Ulvaceae, which comprises the above-mentioned genera.


See references underALGAE.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Los ordenes que presentaron mayor riqueza de especies fueron Ulvales y Cladophorales con ocho y siete especies respectivamente.
NMR spectroscopic characterisation of oligosaccharides from two Ulva rigida ulvan samples (Ulvales, Chlorophyta) degraded by a lyase.
Turbinaria turbinata (Linnaeus) Kuntze C1, C2 CHLOROPHYTA Clase Ulvophyceae Orden Ulvales Kornmanniaceae 48.
Jha, "Differential responses to cadmium induced oxidative stress in marine macroalga Ulva lactuca (Ulvales, Chlorophyta)," BioMetals, vol.
Evidence for multiple introductions of the Pacific green alga Ulva australis Areschoug (Ulvales, Chlorophyta) to the Iberian Peninsula.
Crouan in Maze and Schramm) Schnetter E&W Order Ulvales Family Ulvellaceae Entocladia viridis Reinke E Family Ulvaceae Enteromorpha sp.
Cell-wall polysaccharides from the marine alga Ulva "rigida" (Ulvales, Chlorophyta)--NMR analysis of ulvan oligosaccharides.
Agardh) ouriques & Bouzon (S y C; L) PHYLUM CHLOROPHYTA Orden Ulvales Familia Gayraliaceae Gayralia K.L.