153,268 species and infraspecific names are in the database, 20,952 images, 59,258 bibliographic items, 409,101 distributional records.

Leptophytum W.H.Adey, 1966

Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Corallinophycidae
Order Hapalidiales
Family Mesophyllaceae

Holotype species: Leptophytum laeve Adey

Original publication and holotype designation: Adey, W.H. (1966). The genera Lithothamnium, Leptophytum (nov. gen.) and Phymatolithon in the Gulf of Maine. Hydrobiologia 28: 321-370, 112 figs, tables I-VI.

Taxonomic status: uncertain, requiring further investigation.

Most recent taxonomic treatment adopted: Athanasiadis, A. (2016). Phycologia Europaea Rhodophyta Vol. I. pp. [i]-xxxxviii, 1-762. Thessaloniki: Published and distributed by the author.

Nomenclatural notes
The ICBN rules cited below are those adopted by the Eighteenth International Botanical Congress, Melbourne, Australia, July 2011 (McNeill et al. 2012).

In accordance with ICBN Art. 13.3, the name Leptophytum is treated as pertaining to a non-fossil taxon because its type is based on a non-fossil specimen. No species based on fossil types have been assigned to the genus.

The nomenclature associated with the name Leptophytum is rather complicated. Adey (1966: 324) designated Leptophytum laeve (one of two species originally included in the genus) as holotype species, citing Lithophyllum laeve Strömfelt 1886 as the basis for his name. This means that the generic name Leptophytum is typified (ICBN Art 10.1) by the type of Lithophyllum laeve Strömfelt (1886: 21), even though Lithophyllum laeve Strömfelt is an illegitimate later homonym (ICBN Art. 53.1) of Lithophyllum laeve Kützing (1847: 33).

Because the binomial Lithophyllum laeve Strömfelt is illegitimate, it cannot serve as the basionym for the binomial Leptophytum laeve (ICBN Art. 6.4, 6.6), which also would be illegitimate (as in Leptophytum laeve (Strömfelt) Adey, 1966: 324). Recognizing this, Düwel & Wegeberg (1996: 473), on advice from Paul Silva (as a personal communication), treated Leptophytum leave as a new name (nomen novum) (ICBN Art. 58.1) ascribed solely to W.H. Adey. As a nomen novum, Leptophytum laeve Adey is based (ICBN Art. 7.5, 58.1) on the same type as the illegitimate name, in this case the type of Lithophyllum laeve Strömfelt, cited by Adey (1966: 324) as the basis for his species name. Additional comments on legitimate and illegitimate names [including Lithophyllum lenormandii f. laeve], authorities and dating priority are provided in Woelkerling et al. 2002: 616).

Matters relating to the epitypification of Lithophyllum laeve Strömfelt and use of the generic name Leptophytum are considered below. - (27 Aug 2009) -

Description: Non-geniculate, thin, crust strongly adhering to pebbles and shells, growing with entire thallus attached; thallus surface smooth except for raised conceptacles; multi-filament hypothallium sub-parallel to substrate, mostly arching up to form perithallium, some filaments arching downward, dead-ending on substrate; epithallium absent or of very few (1-3), thin-walled, non-photosynthetic cells; meristem small-celled, intercalary below epithallium; elongation of perithallial cells gradual during burial; double mode of calcification absent; bi/tetrasporangial conceptacles multiporate; male conceptacles with mature spermatangial systems simple, composed of lunate spermatangial mother cells on the floor; spermatangial mother cells cutting off up to 5 spermatangia, dendroid spermatangial mother cells rare; female (uniporate) conceptacles conical; carposporangia produced peripherally around central fertile zone that remains more or less flat; older conceptacles not becoming buried in thallus, but thalli may overgrow one another resulting in conceptacles appearing to be buried.

Information kindly contributed by Paul W. Gabrielson but may now be outdated.

Comments: There are two problems with Leptophytum, the genus created by Adey (1966). The first is that the basionym of the generitype species, Leptophytum laeve, is Lithophyllum laeve Strömfelt (1886), a later homonym of Lithophyllum laeve Kützing 1847, and therefore an illegitimate name. A solution to this problem was recommended by the late, Dr. Paul C. Silva, who proposed that Leptophytum laeve be treated as a new name (Düwel & Wegeberg, 1996, p. 473, cited as P. C. Silva personal communication), a solution that AlgaeBase and Adey et al. (2015) have adopted. The type of the species and genus remains Strömfelt's type material of Lithophyllum laeve.
The second problem is that the holotype is represented by only a single microscope slide that some consider unambiguously to be Leptophytum laeve (Adey et al. 2001) whereas others (Düwel and Wegeberg 1996, Woelkerling et al. 2002) believed that it is "...demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name to a taxon" (McNeill et al. 2012, Article 9.8). Düwel and Wegeberg (1996) proposed an epitype based on material collected from the type locality (topotype material) that upon examination they believed to represent Phymatolithon lenormandii (Areschoug) W.H. Adey, making Leptophytum a synonym of Phymatolithon. Adey et al. (2015) are convinced that Strömfelt's holotype microscope slide is L. laeve based on the non-overlapping pore plate diameters of asexual conceptacles and on the non-overlapping sporangial lengths, both 1.5-2 times larger in L. laeve compared to P. lenormandii, and distinct from all other Subarctic non-geniculate corallines. Both Adey (1966) and Düwel and Wegeberg (1996) were unable to find material at the type locality, and, additionally, L. laeve does not occur intertidally, where Strömfelt's material was said to have been collected. The locality of the type collection may be incorrect or the type material was cast ashore and into a tide pool during the heavy storms that frequent the south coast of Iceland. DNA sequences, using three markers from three specimens (US 169242, US 170538 and US 170934) that were identified by Adey as Leptophytum laeve belong to a genus distinct from both Phymatolithon and Clathromorphum. As the holotype specimen (one microscope slide) has features that agree with the sequenced specimens and that differ from all other Subarctic nongeniculate corallines and the DNA sequences also are distinct from all other Subarctic nongeniculate corallines, Adey et al. (2015) proposed recognition of Leptophytum as a distinct genus and regarded the Düwel and Wegeberg (1996) epitypification as unnecessary.

Numbers of names and species: There are 25 species names in the database at present.

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.

Adey, W.H. (1966). The genera Lithothamnium, Leptophytum (nov. gen.) and Phymatolithon in the Gulf of Maine. Hydrobiologia 28: 321-370, 112 figs, tables I-VI.

Athanasiadis, A. & Adey, W.H. (2006). The genus Leptophytum (Melobesioideae, Corallinales, Rhodophyta) on the Pacific coast of North America. Phycologia 45: 71-115.

Adey, W.H., Athanasiadis, A. & Lebednik, P.A. (2001). Re-instatement of Leptophytum and its type Leptophytum laeve: taxonomy and biogeography of the genera Leptophytum and Phymatolithon (Corallinales, Rhodophyta). European Journal of Phycology 36: 191-204.

Compère, P. (2004). Report of the Committee for Algae: 8. Taxon 53: 1065-1067.

Athanasiadis, A. & Adey, W.H. (2003). Proposal to conserve the name Lithophyllum laeve Stromfelt against L. laeve Kützing (Corallinales, Rhodophyta) with a conserved type. Taxon 52: 342-350, 26 figs, 1 table.

Düwel, L. & Wegeberg, S. (1996). The typification and status of Leptophytum (Corallinaceae, Rhodophyta). Phycologia 35: 470-483.

Foslie, M. (1898). Systematical survey of the Lithothamnia. Det Kongelige Norske Videnskabers Selskabs Skrifter 1898(2): 1-7.

Kützing, F.T. (1847). Diagnosen und Bemerkungen zu neuen oder kritischen Algen. Botanische Zeitung 5: 1-5, 22-25, 33-38, 52-55, 164-167, 177-180, 193-198, 219-223.

Maneveldt, G.W., Chamberlain, Y.M. & Keats, D.W. (2008). A catalogue with keys to the non-geniculate coralline algae (Corallinales, Rhodophyta) of South Africa. South African Journal of Botany 74 : 555-566.

McNeill, J., Barrie, F.R., Burdet, H.M., Demouline, V., Hawksworth, D.L., Marhold, K., Nicolson, D.H., Prado, J., Silva, P.C., Skog, J.E., Wiersema, J.H. & Turland, N.J. (2006). International Code of Botanical Nomenclature (Vienna Code) adopted by the Seventeenth International Botancial Congress Vienna, Austria, July 2005. pp. [i-iv], v-xviii + 1-568. Liechtenstein: A.R.G. Gantner Verlag.

Strömfelt, H.F.G. (1886). Om algvegetationen vid Islands Kuster. pp. 1-89. Göteborg: Akademisk Afhandling.

Woelkerling, W.J., Furnari, G. & Cormaci, M. (2002). Leptophytum (Corallinaceae, Rhodophyta): to be or not to be? - that is the question, but what is the answer?. Australian Systematic Botany 15: 597-618.

Adey, W.H., Hernández-Kantún, J.J., Johnson, G. & Gabrielson, P.W. (2015). DNA sequencing, anatomy, and calcification patterns support a monophyletic, subarctic, carbonate reef-forming Clathromorphum (Hapalidiaceae, Corallinales, Rhodophyta). Journal of Phycology 51(1): 189-203.

Bailey, J.C. & Chapman, R.L. (1998). A phylogenetic study of the corallinales (Rhodophyta) based on nuclear small-subunit rRNA gene sequences. Journal of Phycology 34: 692-705, 5 figs, 3 tables.

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

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: 30 November 2017 by M.D. Guiry

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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 18 October 2018.

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