Sep 092016
 
Sphaeropcaros texanus photographed by David Long (Long 33162)

European material of Sphaerocarpos texanus, photographed by David Long (Long 33162)

The Sphaerocarpales (or “Bottle Liverworts”) form a very distinct group in the complex thalloid liverworts, with ca. 30 species in five genera: originally the group just included Geothallus (monospecific), Sphaerocarpos (8-9 species) and Riella (ca. 20 species), with two more monospecific genera, Austroriella and Monocarpus, added within the last few years. All five genera have very unusual, and highly reduced, thallus morphologies. With the exception of Monocarpus, they also all enclose their sex organs (or gametangia – the antheridia and archegonia) in inflated flask-shaped bottles (as can be seen in the accompanying photograph). This feature sets them apart from all other liverworts. All of them are adapted to extreme habitats, including arable fields, hot arid regions, seasonal lakes and pools, and salt pans.

A worldwide revision of the second largest genus of the group, Sphaerocarpos, is over 100 years old (Haynes 1910); other revisional work focuses on individual geographic areas, including South Africa (Proskauer 1955), North America (Haynes & Howe 1923, Frye & Clark 1937, Schuster 1992, Timme 2003), California (Howe 1899), Europe (Reimers 1936, Müller 1954), and France (Douin 1907). No revisions have been made for large areas including Australia, Asia and South America, and most of the work predates any DNA-based concepts of plant identification or species relationships. Bringing the taxonomy of Sphaerocarpos into the 21st century, Dr Daniela Schill spent 18 months (2007-2009) at RBGE on a Sibbald Trust-funded project to compile a world-wide taxonomic revision of the genus. Two field expeditions fed into the project, with Dr David Long collecting European species in Portugal in April 2007, and Daniela collecting North American species in California in March 2008 (funded by the Peter Davis Expedition Fund).

Spore SEMs of Sphaerocarpus drewiae, taken by Daniela Schill

Spore tetrads of Sphaerocarpos drewiae, SEMs taken by, and plate prepared by, Daniela Schill

Daniela’s work is based on morphological and anatomical characters, including spore characters that she observed using Scanning Electron Microscopy (SEM). Her aim has been to produce identification keys to the species, species descriptions, species lists, synonyms, botanical drawings, distribution maps, and ecological, nomenclatural and taxonomical notes. Although the study is not yet published, much of it, including SEM plates for spores from the ca. 9 different species (as seen on the right), is complete.

In parallel, RBGE staff have also been sequencing multiple accessions of all available Sphaerocarpos species, producing data that has helped inform some of Daniela’s taxonomic decisions, and that also allow us to generate a stand-alone phylogeny for the genus.

This research will lead to some taxonomic changes. For example, European Sphaerocarpos texanus plants differ from American S. texanus, both in their DNA sequences and in their spore characters, and so they are likely to be considered a separate species. Furthermore, European Sphaerocarpos michelii material includes three different forms based on spore characters; these are also confirmed by molecular research, and may be recognised at or below the rank of species.

 

References:

Cargill, D.C. & J. Milne. 2013. A new terrestrial genus and species within the aquatic liverwort family Riellaceae (Sphaerocarpales) from Australia. Polish Botanical Journal 58(1): 71-80.

Douin R. 1907. Les Sphaerocarpus français. Revue Bryologique 34(6): 105-112.

Frye T.C. & L. Clark. 1937. Hepaticae of North America. University of Washington Publications in Biology 6: 105-113.

Haynes C.C. 1910. Sphaerocarpos hians sp. nov., with a revision of the genus and illustrations of the species. Bulletin of the Torrey Botanical Club 37(5): 215-230.

Haynes C.C. & M.A. Howe. 1923. Sphaerocarpales. North American Flora 14: 1-8.

Howe  M.A. 1899. The hepaticae and anthocerotes of California. Memoirs of the Torrey Botanical Club 7: 64-70.

Müller K. 1954. Die Lebermoose Europas. In: Rabenhorst’s Kryptogamenflora von Deutschland, Österreich und der Schweiz. 3. Auflage. Volume VI. Part 1. Leipzig, Akademische Verlagsgesellschaft Geest & Portig K.-G., Johnson Reprint Corporation (1971), New York, London.

Proskauer J. 1955. The Sphaerocarpales of South Africa. The Journal of South African Botany 21: 63-75.

Reimers H. 1936. Revision des europäischen Sphaerocarpus-Materials im Berliner Herbar. Hedwigia 76: 153-164.

Schill D.B., L. Miserere & D.G.Long. 2009. Typification of Sphaerocarpos michelii Bellardi, S. terrestris Sm. and Targionia sphaerocarpos Dicks. (Marchantiophyta, Sphaerocarpaceae). Taxon 58(2): 638-640.

Schuster R.M. 1992. Sphaerocarpales. In: The hepaticae and anthocerotae of North America V. Field Museum of Natural History, Chicago: 799-827.

Timme S.L. 2003. Sphaerocarpaceae. In: Bryophyte Flora of North America, Provisional Publication.

 

Jul 172015
 

Twenty-five participants from 13 countries have just attended a symposium on complex thalloid liverworts in Edinburgh #Marchantia2015. The meeting also included two teleconferences (from Australia, John Bowman, Monash University, and from the USA, Stuart McDaniel, University of Florida) and one recorded presentation (Péter Szövényi, University of Zurich).

#Marchantia2015 Complex Thalloid symposium at RBGE

#Marchantia2015 Complex Thalloid symposium at RBGE

Seated (left to right): Robbert Gradstein (MNHN Paris), Hanna Kijak (Adam Mickiewicz University), David Long (RBGE), Jeff Duckett (Natural History Museum London), Juan Carlos Villarreal (RBGE), Laura Forrest (RBGE)
Standing (left to right): Kumar Shantanu (University of Delhi), David Bell (University of British Columbia), Masaki Shimamura (Hiroshima University), Liam Dolan (University of Oxford), Neil Bell (RBGE), Halina Pietrykowska (Adam Mickiewicz University), Des Callaghan (bryophytesurveys.co.uk), Liz Kungu (RBGE), Izabela Sierocka (Adam Mickiewicz University), David Chamberlain (RBGE), Catherine Reeb (MNHN Paris), Sam Brockington (University of Cambridge), Aline Horwath (University of Cambridge), Bernardo Pollak (University of Cambridge), Silvia Pressel (Natural History Museum London).

Not shown are Alistair McCormick (University of Edinburgh), Cymon Cox (CCMAR), and Michelle Hollingsworth, Gunnar Ovstebo, Katie Emelianova and YunYu Chen (RBGE).

Following an introduction by the Regius Keeper, Simon Milne, the first day comprised of talks on the Diversity of complex thalloid liverworts (David G. Long), Amphitropical disjunctions in the complex thalloids  (Robbert Gradstein), The beginnings of microtranscriptome evolution in plants (Halina Pietrykowska, P. Piszczałka, S. Alaba, A. Pacak, I. Sierocka, P. Nuc, K. Singh, P. Plewka, A. Sulkowska, A.Jarmolowski, W.M. Karlowski, Z. Szweykowska-Kulinska), On Monocarpus (Monocarpaceae, Marchantiopsida), an isolated salt-pan complex thalloid liverwort (Laura L. Forrest, D.G. Long, D.C. Cargill, M.L. Hart, J. Milne, D.B. Schill, R.D. Seppelt, J.C. Villarreal), Sex chromosome evolution in haploid dioecy (e-talk) (Peter Szövényi, S.F. McDaniel, A. Payton, M. Ricca), Food- and water-conducting systems in complex thalloids with sexual reproduction thrown in (Jeff Duckett, S. Pressel) and Get off my turf! – Contrasting strategies for habitat specialisation by different bryophyte lifeforms (Aline Horwath). There were also two short presentations, one on the Journal of Bryology (Liz Kungu), and the other on NSF Genealogy of Life (GoLife) grant “Building a Comprehensive Evolutionary History of Flagellate Plants” (e-talk) (Stu McDaniel).

RBGE's Complex Thalloid symposium in full flow

RBGE’s Complex Thalloid symposium in full flow

On the second day of the meeting, talks comprised An update on the Marchantia genome (e-talk) (John Bowman, S. K. Floyd,T. Kochi, K.T. Yamato, K. Ishizaki, K. Berry, Jenkins, J. Schmutz), Evolution of sexual systems in complex thalloids (Masaki Shimamura), Development and evolution of the plant soil interface (Liam Dolan), Scratching the surface: The Marchantia Cuticle (Sam Brockington, S. Pressel, J. Duckett), An overview of Malagasy Marchantiidae (Catherine Reeb), Fungal associations in complex thalloids (Silvia Pressel, J.G. Duckett), RNA sequencing as a method of choice for the identification of genes differentially expressed between male and female gametophytes producing sex organs in simple thalloid liverwort Pellia endiviifolia (Izabela Sierocka, S. Alaba, W. Karłowski, Z. Szweykowska-Kulinska), and Divergence times, evolution of morphological complexity and sexual systems in a lineage with a slow molecular rate (Juan Carlos Villarreal, B.J. Crandall-Stotler, M.L. Hart, D.G. Long, L.L. Forrest).

 Thanks to RBGE and the Sibbald Trust, for logistic support and funding for the symposium.