A new Indian species of Riccia L. with connections to northern Australia

ABSTRACT

Introduction. During a recent explorative field trip to the Western Ghats a new species of Riccia was discovered with possible links to the northern Australian species, Riccia caroliniana Na-Thalang.

Key Results. Morphological similarities between the new species, R. sahyadrica and R. caroliniana include the ventral positioning of the photosynthetic tissue in the ventral section of the thallus in specialised structures known as ventral lamellae. These form a v-shaped patterning along the ventral surface of the thallus and are unique to these two species. Both species also bear similar spores with differences in the micro-ornamentation. Differences between the two species also extend to sexual condition, whereby R. caroliniana is dioicous and R. sahyadrica is monoicous.

Conclusions. A new species, Riccia sahyadrica Manju & Cargill is described and illustrated and compared to the only other morphologically similar species, R. caroliniana endemic to northern Australia. Both species possess the unique characteristic of bearing ventral photosynthetic tissue in contrast to the dorsal position typically seen in all other Riccia species.

KEYWORDS:

• Kerala
• Ricciaceae
• submerged
• Western Ghats
• Viridisquamata

Acknowledgements

The first author would like to thank Dr C. N. Manju for the opportunity to study this unique Indian Riccia and would also like to thank Drs Cécile Gueidan and Sue Fyfe and Mr Brendan Lepschi for comments on the first draft. The other authors (MCN, KPR, CVK and KMD) are thankful to the authorities of the Zamorin's Guruvayurappan College for facilities. They are indebted to the Kerala State Council for Science Technology & Environment (KSCSTE), Thiruvananthapuram, Kerala for the award of the research project on the Bryophytes of Peechi Wildlife Sanctuary; to the Kerala Forest and Wildlife Department for the collection permit; and their staff members at the Peechi Wildlife Sanctuary for the support extended during the field studies. We thank the staff members of Centre for Medicinal Plants Research, Kottakkal for their assistance in preparing the SEM photos.

Notes on contributors

Dr D. Christine Cargill is the curator of the cryptogam collection at the Australian National Herbarium (CANB) and is a bryophyte taxonomist and systematist specialising in Australian hornworts and liverworts in the families Fossombroniaceae, Ricciaceae and Aytoniaceae.

Dr C. N. Manju is Assistant Professor of Botany, and has been studying the diversity and ecology of bryophytes of the Western Ghats of India since 2001.

Ms K. M. Deepa is a PhD student supervised by Dr C. N. Manju, and is studying the diversity of Marchantiales of South India.

Ms V. K. Chandini is a PhD student supervised by Dr. C. N. Manju, and studying the diversity of bryophytes of Kerala.

Dr K. P. Rajesh is Assistant Professor of Botany, and has been studying the diversity and ecology of bryophytes, pteridophytes and angiosperms of southern India since 1994.

ORCID

D. C. Cargill http://orcid.org/0000-0001-8390-3245

K. P. Rajesh http://orcid.org/0000-0003-1967-5174

Additional information

Funding

This work was supported by the Kerala State Council for Science, Technology and Environment [grant number 031/SRSLS/2014/CSTE].