Apoglossum (J.Agardh) J.Agardh, 1898

Lectotype species: Apoglossum ruscifolium (Turner) J.Agardh

Original publication: Agardh, J.G. (1898). Species genera et ordines algarum, seu descriptiones succinctae specierum, generum et ordinum, quibus algarum regnum constituitur. Voluminis Tertii, Pars Tertia. De dispositione Delesseriearum curae posteriores. pp. i-vii, 1-239. Lundae [Lund]: apud C.W.K. Gleerup.

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Type designated in: Kylin, H. (1924). Studien ΓΌber die Delesseriaceen. Acta Universitatis Lundensis 20(6): 1-111, 80 figs.

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Description: Thallus made up of prostrate axes carrying erect laminae (a few centimeters high) and/or decumbent, stipitate, lanceolate-ovate in shape, membranous in consistency and provided with an evident median decurrent rib, usually strongly corticated by descending rhizoidal filaments. The branches are endogenous and originate from the rib median. The laminae are monostromatic, except in the midrib, and are made up of cellular filaments branched up to the 4th-5th order; the cellular filaments of 2nd order, the only ones that normally reach the margin, form microscopic veins also recognizable by the slightly elongated cells; sometimes even 3rd order rows can form veins following subsequent elongation of their cells. The apex of the blades can be pointed, rounded or retused; the apical cell divides transversely and produces a primary or axial filament which is always devoid of intercalary divisions; these are also absent in 1st order cell rows, but they are frequent and abundant in the 2nd order and higher order rows; this makes the original organization of the cell rows of the lamina is confused. The 2nd order rows, which all reach the margin of the lamina, carry abaxial 3rd order rows in an ascending direction that do not reach the edge of the lamina; the rows of 3rd order carry adaxial 4th order rows in the ascending direction, which they do not reach the margin; these, in turn, carry abaxial 5th order rows in an ascending direction, which do not reach the margin. This alternation of abaxial rows with adaxial rows and again with abaxial rows, according to Lin et al. (op, cit.) is typical of the Apoglossum genus. Dioecious plants. The spermatocysts are grouped in radially elongated sori and regularly arranged on the two sides of the median rib, on both faces of the foil; outwards they are delimited by a large sterile portion of the lamina. THE procarps are formed in the upper part on both sides of the midrib; they they consist of a carpogonial branch of 4 cells and two sterile unicellular groups. The gonimoblasts, several times subdichotomous, bear pyriform carposporocysts in chains branched terminals. The cystocarps, sessile and ostiolate with central ostiole carried on one beak-shaped protrusion, they have a pericarp of 3-4-5 layers of cells. The tetrasporocysts are grouped in continuous or discontinuous sori along the two sides of the midrib; when discontinuous, they are interrupted by sterile portions of the foil; the tetrasporocysts are covered by an external cortex.

Information contributed by: Cormaci & al. (2023: 550).. The most recent alteration to this page was made on 2023-12-11 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 neuter.

Most recent taxonomic treatment adopted: Cormaci, M., Furnari, G., Alongi, G. & Serio, D. coautrice per le Ceramieae (2023). Flora marina bentonica del Mediterraneo: Rhodophyta - Rhodymeniophycidae III: Ceramiales I (RHODOMELACEAE escluse). Bollettino Accademia Gioenia di Scienze Naturali in Catania 56(386): 81-621, 109 pls.

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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=32774

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 11 December 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 18 April 2024

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