Bulbochaete C.Agardh, 1817

Holotype species: Bulbochaete setigera C.Agardh ex Hirn

Original publication and holotype designation: Agardh, C.A. (1817). Synopsis algarum Scandinaviae, adjecta dispositione universali algarum. pp. [i]-xl, [1]-135. Lundae [Lund]: Ex officina Berlingiana.

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Description: Uniseriate filaments with extensive unilateral branching; usually attached to substratum by differentiated holdfast cells. Vegetative cells uninucleate, highly vacuolate, and with a large reticulate, parietal chloroplast containing one to many (usually) pyrenoids. Pyrenoid matrix penetrated by numerous, branched, cytoplasmic channels. Vegetative filaments with cells of two morphological types 1) basal holdfast cells, 2) nearly cylindrical intercalary cells, that are often somewhat greater in width at apical end, and 3) smaller, terminal, "hair" cells with bulbous or swollen base and bearing a much elongated, slender, hair-like, cytoplasmic appendage. Hair cells one of most conspicuous and distinctive features of genus. Cell division restricted to basal cells of main filament and branches, or to intercalary cells which give rise to branching. Asexual reproduction by multiflagellate zoospores, germination of akinetes, or fragmentation of filaments. Sexual reproduction oogamous; monoecious or dioecious; some species nannandrous with dwarf male filaments derived from androspores. Two successive divisions of oogonial mother cell produce large, swollen oogonium subtended by two supporting (suffultory) cells. Single egg in oogonium fertilized by much smaller, multiflagellate male gamete. Resulting zygote (oospore) gradually turns red and develops a thick wall with species specific surface ornamentation. Meiosis thought to be zygotic. Zygote germination typically produces four motile cells, each capable of attaching to substratum and producing a new filament through repeated cell division.

Information contributed by: L.R. Hoffman. The most recent alteration to this page was made on 2015-12-30 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: Huxley, R. & Pentecost, A. (2002). Order Oedogoniales. In: The Freshwater Algal Flora of the British Isles. An identification guide to freshwater and terrestrial algae. (John, D.M., Whitton, B.A. & Brook, A.J. Eds), pp. 409-432. Cambridge: Cambridge University Press.

Comments: Bulbochaete occurs in a wide variety of freshwater habitats; only a few species are known from brackish waters. Normally epiphytic and attached to aquatic vegetation by basal holdfast cell; occasionally free-floating. Most frequently encountered in small bodies of shallow, standing water such as ponds, small lakes, and ditches. Cosmopolitan with greatest abundance of species in temperate and subtropical regions. Shares with other genera in Oedogoniales the following unique features of cell division (1) formation of ring of new cell wall material near anterior end of each dividing cell; (2) rupture of parental cell wall in this position; and (3) the gradual extension of ring of wall material to form new cylindrical wall components distributed to both daughter cells following cytokinesis. Cell division also leads to formation of an "apical cap" marking the cell wall near apex of apical-most daughter cell. Combined light and electron microscopic investigations have clarified many structural and developmental aspects of cell division, hair cell formation, and gametogenesis.

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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=43422

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 30 December 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 November 2024