152,895 species and infraspecific names are in the database, 20,947 images, 59,136 bibliographic items, 408,271 distributional records.

Halichrysis (J.Agardh) F.Schmitz, 1889

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Rhodymeniophycidae
Order Rhodymeniales
Family Rhodymeniaceae

Lectotype species: Halichrysis depressa (J.Agardh) F.Schmitz

Original publication:Schmitz, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora oder Allgemeine botanische Zeitung 72: 435-456, pl. XXI.
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Type designated in Agardh, J.G. (1876). Species genera et ordines algarum, seu descriptiones succinctae specierum, generum et ordinum, quibus algarum regnum constituitur. Volumen tertium: de Florideis curae posteriores. Part 1. pp. [ii*-iii*], [i]-[viï], [1]-724. Lipsiae [Leipzig]: C.W.K. Gleerup.
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Precise date of publication20 Dec 1889

Taxonomic status: currently recognized as a distinct genus.

Gender: This genus name is currently treated as feminine.

Most recent taxonomic treatment adopted: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.

Nomenclatural notes
The type of the genus Halichrysis (J.Agardh) F.Schmitz is the type of Chrysymenia sect. Halichrysis J. G. Agardh, Sp. Alg. 2: 211. 1851 as selected by Agardh (1876: 136, 321) (ING), upon which the genus Halichrysis (J.Agardh) F.Schmitz is based. - (24 Jan 2017) - M.D. Guiry

Description: Thallus peltate or imbricate, sometimes iridescent, blades arising from a branched or unbranched, cylindrical stipe, frequently anastomosing, spreading and imbricate when mature, margins often recurving towards the substratum. Construction multiaxial, cortex of 1-2 layers of small cells, medulla of several layers of thick-walled, colourless cells. Gametangial plants dioecious; spermatangial sori superficial on one or both surfaces. Spermatangia formed on terminal cortical cells. Procarpic, carpogonial branches in cortex, 3-celled, borne in pairs on a large supporting cell bearing a single, 2-celled auxiliary cell branch. Gonimoblast developing outwards. Cystocarps ostiolate, scattered, on one or both surfaces of the thallus, never coronate, strongly protruding outwards, tela arachnoidea absent, columnar gonimoblast persisting. Tetrasporangia formed in an terminal position from cortical cells, forming on the upper or lower surfaces, or both, occasionally in nemathecioid sori. Spores regularly cruciately arranged. Although nothing is known of the growth in culture or of the life history, it is likely that species of the genus have a ‘Polysiphonia-type’ life history.

Information contributed by: M.D. Guiry. The most recent alteration to this page was made on 24 Jan 2017 by M.D. Guiry.

Comments: The genus Halichrysis is named for the iridescence apparent in live specimens of the type species; such iridescence is a feature of many peltate or prostrately groing algae, including some belonging to other families of red algae, such as Drachiella (Delesseriaceae, Maggs and Hommersand, 1993). The phenomenon is poorly understood. Two other genera of Rhodymeniales form peltate blades: Maripelta and Sciadophycus (q.v.); in both of these genera a medulla composed of a single layer of large cells is formed. In Maripelta (q.v.), the blades are not imbricate and reattachment does not take place, and the tetrasporangia are formed in an intercalary position. In Sciadaophycus, although the tetrasporangia are formed in a terminal position similar to those of Halichrysis, a tela arachnoidea is formed in the cystocarp. Details of the development of the procarp and of the cystocarp are known only for H. concrescens; the formation of two carpogonial branches on the same supporting cell is unique amongst the Rhodymeniaceae and is otherwise only found in species of Gastroclonium and Chylocladia. Huvé and Huvé (1976) have shown that early reports of a tela arachnoidea in H. concrescens are incorrect and a cellular network does not persist in the cystocarp. In recent years, inclusion of the genera Weberella (Huvé and Huvé 1977) and Drouetia (Norris 1991) in Halichrysis has been proposed on the basis of the peltate or imbricate habit of species of these genera, the presence of a polystromatic medulla and the absence of a tela arachnoidea. However, full details of the reproduction of the type species of these genera are unknown, particularly with regard to the structure of the procarp, and this requires further study, given the structure of the procarp in H. concrescens. Halichrysis depressa is known only from the area around the Straits of Gibraltar (Tangier, Algeria and Ceuta, Spain) where it grows at depths of 4-10 m; other reports are doubtfully correct (Huvé and Huvé 1976). H. peltata (W.R. Taylor) Huvé et Huvéhas been referred to Asteromenia (q.v.). H. coalescens (Farlow) R.E. Norris et A.J.K. Millar in R.E. Norris is found in eastern Australia (Millar 1990), South Africa, Indonesia, and the Galápagos Is. where it grows in the lower intertidal and at depths of up to 20 m. H. japonica Segawa is known only from Japan. H. micans (Hauptfleisch in Engler et Prantl) Huvé et Huvé is known from Borneo, Indonesia, Vietnam and Japan. Chrysymenia concrescens J. G. Agardh, described from Australia, is known only from the type material, and was transferred to Halichrysis by De Toni (1900). Millar (1990) re-examined the type material and suggested that the species was best placed in Halichrysis.

Numbers of names and species: There are 11 species names in the database at present, of which 7 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Click here to also show infraspecific names in the list below.

References
Saunders, G.W., Lane, C.E., Schneider, C.W. & Kraft, G.T. (2006). Unraveling the Asteromenia peltata species complex with clarification of the genera Halichrysis and Drouetia (Rhodymeniaceae, Rhodophyta). Canadian Journal of Botany 84: 1581-1607, 83 figs, 3 tables.

Huvé, P. & Huvé, H. (1977). Notes de nomenclature algale. I. - Le genre Halichrysis (J. Agardh 1851 emend J. Agardh1876) Schousboe mscr. in Bornet 1892 (Rhodyméniales, Rhodyméniacées). Bulletin de la Société Phycologique de France 22: 99-107.

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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 24 January 2017 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=33252

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 September 2018.

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