Nitellopsis Hy, 1889

Holotype species: Nitellopsis stelligera (Bauer) Hy

Original publication and holotype designation: Hy, F. (1889). Sur les modes de ramification et cortication dans la Famille des Characées. Bulletin de la Société Botanique de France 36: 393-398.

Fossil: This is a genus of fossil species, or a genus with a fossil type species, or a genus the type species of which was originally described as a fossil.

Description: Erect, branched plants, attached to substratum with rhizoids. Rhizoids numerous, multicellular, branching, and colorless. Primary axes with alternating sequence of nodal and internodal cells developed from apical cell. Each apical cell derivative divides transversely and the daughter cells develop into a multicellular nodal complex with 6-12 peripheral cells and its internodal cell, respectively. Each node bears a whorl of ecorticate determinate branchlets 2-many cells long. Indeterminate axes develop in axils of branchlets at scattered nodes. Stipulodes absent. Internodal cells enlarge to several cm in length. Plants without cortication. Cells mostly uninucleate, however, internodal cells with a few large irregular nuclei produced by amitosis. Cytoplasm distinctly layers with external stationary layer with rows of helicoidally aligned chloroplasts (ectoplasm) and internal streaming layer with nuclei, mitochondria (endoplasm); cells with large central vacuole. Asexual reproduction by vegetative propagation from rhizoids as well as adventitious development from nodal cells of plants buried in sediments. One to five spherical unicellular or multicellular masses termed bulbils produced laterally on nodes of rhizoids; bulbils with white to cream colored and with numerous starch grains. Secondary bulbils may be formed from initial ones; germination via rhizoid production. Calcium carbonate (calcite) deposition associated with developing oogonia. Similar to other Chareae with one tier of five crown cells on oosporangium. Oosphere producing a single sterile cell similar to Chara. Life history presumably zygotic with meiosis occurring during oospore germination. Nitellopsis cosmopolitan in freshwater.

Information contributed by: D. Garbary. The most recent alteration to this page was made on 2024-08-20 by E.A. Molinari Novoa.

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: Feist, M., Grambast-Fessard, N., Guerlesquin, M., Karol, K., Lu, H., McCourt, R.M., Wang, Q. & Zhang, S. (2005). Treatise on Invertebrate Paleontology. Charophyta. Vol. B(1.1) pp. xvi, 170, 79 figures, 9 tables. Kansas: Geological Society of America & University of Kansas Press.

Comments: Two endemic and one cosmopolitan species (N. obtusa) are present in North America. Subfossil oospores can be identified from lake sediments. Nitellopsis obtusa used a model system in studies of cytoplasmic streaming. Although vegetatively similar to Nitella, reproductive morphology places Nitellopsis in Charae. Semicompound starch grains (to 170 &m) of Nitellopsis may also distinguish genus from Lamprothamnion with simple starch grains 60-70 (&m) and Lycnothamnus (85-90 &m). Oosporangia similar to Nitellopsis and Lamprothamnion described as Tectochara from the Oligocene. Species distinguished based on branchlet morphology. Sperm ultrastructure remains unstudied and should provide key information on relationships with Chara, Lycnothamnus and Lamprothamnion.

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Contributors
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=44295

Citing AlgaeBase
Cite this record as:
E.A. Molinari Novoa in Guiry, M.D. & Guiry, G.M. 20 August 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024