Dasyclonium J.Agardh, 1894

Holotype species: Dasyclonium acicarpum J.Agardh

Currently accepted name for the type species: Dasyclonium incisum (J.Agardh) Kylin

Original publication and holotype designation: Agardh, J.G. (1894). Analecta algologica. Continuatio II. Lunds Universitets ÅrsSkrift, Andra Afdelningen, Kongl. Fysiografiska Sällskapets i Lund Handlingar 30(7): 1-99, 1 plate.

Request PDF

Description: Prostrate, polysiphonous, dorsiventral thalli, usually epiphytic, apical region curved dorsally, often circinate. Uncorticated and with holdfasts mostly formed in proximal parts of plants, comprised of several multicellular rhizoids on ventral side of 2 adjacent segments; usually 1-3 segments apart. Axis with an exogenously formed determinate branchlet, latero-dorsal, on every other segment, regularly alternating and forming two rows on axis, 3 segments intervene between two branchlets on any one side. Determinate branchlet axes up to ~18 segments long, secundly arranged secondary and sometimes additional orders of branching occur; pericentral cells often fewer than in axis; sometimes monosiphonous, apical cells often apiculate. Congenital fusion of branchlets within the determinate branchlet unit occurs, in varying degrees, in some species, apical regions often remaining free and forming teeth. Species with congenitally fused filaments in determinate branchlets develop only 1-2 pericentrals in lateral positions resulting in monostromatic bladelets. Indeterminate branches endogenously derived, on segments immediately proximal to determinate branchlets and on the same side; sometimes occurring less regularly and often remaining dormant. Prostrate axis developed from determinate radially or bilaterally oriented, erect juvenile thallus; the basal polysiphonous segment endogenously producing a single indeterminate prostrate axis (Scagel 1953). Gametophyte reproductive structures on secondary laterals of determinate branchlets. Procarps on suprabasal segment of lowermost laterals of a determinate branchlets; distal part of secondary lateral evanescent as cystocarp matures. Spermatangial capitula triradiate and on or replacing 2nd-3rd lowermost secondary laterals; marginal cells sterile. Tetrasporangia formed on distal indeterminate laterals of the second order; determinate branchlets in fertile region reduced and sometimes appear only as short spines. Primary fertile axis ~10-12 segments long, each segment producing a single tetrasporangium which occur in a straight dorsal row. Three cover cells on each sporangium dividing to produce 5-7.

Information contributed by: R.E. Norris. The most recent alteration to this page was made on 2010-10-06 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Kylin, H. (1956). Die Gattungen der Rhodophyceen. pp. i-xv, 1-673, 458 figs. Lund: C.W.K. Gleerups.

Comments: Lower littoral to sublittoral, usually epiphytic; New Zealand, including subantarctic islands, southern Australia, South Africa and Japan.

Verification of Data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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=35635

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 06 October 2010. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 23 November 2024