Chara Linnaeus, 1753
Lectotype species: Chara vulgaris Linnaeus
Original publication: Linnaeus, C. (1753). Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Vol. 2 pp. [i], 561-1200, [1-30, index], [i, err.]. Holmiae [Stockholm]: Impensis Laurentii Salvii.
Type designated in: Wood, R.D. (1960). Linnaean types for Characeae. Transactions of the American Microscopical Society 79: 219-226.
Description: Erect, branched plants mostly 30-100 cm long and usually calcified; attached by numerous rhizoids. Colorless rhizoids multicellular and branched. Primary indeterminate axes with alternating sequence of nodal and internodal cells developed from apical cell. Each apical cell derivative divides transversely and daughter cells develop into multicellular nodal complex with 6-12 peripheral cells and its internodal cell, respectively. Each node bears a whorl of 6-16 corticate or ecorticate determinate branchlets 2-many cells long. Indeterminate axes develop singly in the axes of branchlets at scattered nodes. At base of each node, one or two tiers of spinous to blunt cells (stipulodes) present in most species. Internodal cells enlarge considerably (up to several cm long). Internodes covered with files of cortical cells growing up and down from node with solitary to clustered spinous cells present or absent; some species ecorticate. Cells mostly uninucleate, however, internodal cells with a few large irregular nuclei produced by amitosis. Cells interconnected with numerous plasmodesmata. Cytoplasm distinctly layered with external stationary layer with rows of helicoidally aligned chloroplasts (ectoplasm) and internal streaming layer with nuclei and mitochondria (endoplasm); cells with large central vacuole. Asexual reproduction by vegetative propagation from rhizoids and adventitious development from nodal cells of plants buried in sediments, or by bulbils (see Nitellopsis). Sexual reproduction always oogamous with gametes produced in complex, multicellular antheridia and oosporangia produced adaxially on branchlet nodes. Species unisexual or bisexual, in the former with single gametangium at each node. In bisexual plants gametangia mostly paired with the antheridium borne below oogonium; gametangia develop simultaneously or with antheridia first. Morphology of mature antheridia and sperm and oosporangia and oospores as described for Lamprothamnion or Nitella. Following fertilization compound oosporangial wall develops derived from both entheathing cells and fertilized oosphere, with outer calcified layer. Zygote germination associated with development of protonemal stage that undergoes divisions to form large and small cells. Primary axes develop as lateral branches of protonema. The life history is presumably zygotic, however, the position of meiosis not widely studied. Haploid chromosome numbers in dioecious species 14-28 with mostly higher counts in monoecious species (n= 14-70). Haploid chromosome numbers of 14, 28 and 56 suggest origin of new species through hybridization and polyploidization. Although vegetative thallus haploid, measurements of DNA in C. vulgaris show at least 70% of nuclei with greater than 2C DNA.
Information contributed by: D.J.Garbary & K. Renzaglia. The most recent alteration to this page was made on 2020-12-29 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Spencer, M.A., Irvine, L.M. & Jarvis, C.E. (2009). Typification of Linnaean names relevant to algal nomenclature. Taxon 58(1): 237-260.
Comments: Chara cosmopolitan in fresh to slightly brackish water; endemic species present on all continents (except Antarctica). Unisexual (i.e. dieocious) species tend to be endemic; bisexual (i.e., monoecious) species more widely distributed especially on oceanic islands. Patterns of endemism and species relationships consistent with genus having arisen on Pangea. Subfossil oospores can be identified from lake sediments. In rhizoids, settlement of statoliths necessary for gravitropic response and statolith movement actin mediated. Tip growth extensively studied in rhizoids. Morphogenetically and physiologically thallus highly integrated with seasonal changes in morphogenesis, electrophysiology and cell-to-cell communication between cells of nodes and between internodes. Chara spp. widely used as model systems in studies of ion transport and electrophysiology. Extracellular current patterns disrupted on exposure of cells to microtubule inhibitors, suggesting microtubular regulation of spatial patterns of plasma-membrane transport events. Antheridial development and spermatogenesis extensively examined, and detailed studies have been carried out including ultrastructure of antheridial walls, cell-cell communication, DNA and protein synthesis, ultrastructure of plasmodesmata, mucilage production, and sperm morphogenesis and ultrastructure. Cytokinesis via cell plate formation within phragmoplast typical of charophytes and land plants. Genus with complex infrageneric classification at section and subsection ranks. Species distinguished by patterns of cortication, details of nodal and oogonial morphology, and ultrastructural features associated with surface ornamentation of oosporangial walls. Mitosis similar to higher plants except in apparent absence of preprophase band and in persistence of nucleolar material. Plants may be highly plastic, e.g., the typically corticated C. canescens forming uncorticated plants, and morphs with stalked oosporangia. Crossing studies show that populations within species often reproductively isolated, and that hybridization between morphologically distinct species absent. Genus (and Charales in general) of considerable phylogenetic importance in that complex implicated either as possible sister group of all land plants or as derived from primitive land plants by reduction.
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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.
Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43352
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 29 December 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 27 March 2023