Dicranum scottianum Turner (Dicranaceae): synonyms, a type and the correct author

ABSTRACT

Introduction. The moss Dicranum scottianum Turner, described based on material collected in Ireland by Robert Scott, is currently known from Europe and Macaronesia (Canary Islands and the Azores). The previously proposed authorship of ‘Turner ex Robt. Scott’ and lectotype for this name proved to be erroneous.

Methods. Over 60 herbarium specimens, including types, of D. scottianum and putative allies were examined with the aim of outlining the diagnostic features of the taxon or taxa concerned, and establishing any necessary synonymy.

Key results. The true authorship of Dicranum scottianum by Turner is re-established, and the name is effectively lectotypified with extant original material from BM. The type specimen and some subsequent collections of the species are described and illustrated. New nomenclatural synonyms of D. scottianum (namely Dicranum canariense Hampe ex Müll.Hal., D. erythrodontium Hampe ex Müll.Hal. and Orthodicranum allorgei J.J.Amann & Loeske) are detailed.

Conclusions. Dicranum scottianum is characterised by its asymmetrical leaves with one side of the leaf wider than the other, the difference in the angle of insertion of the lamina with respect to the costa (one side of the leaf is inserted at a 45° angle and the other is plane but widely incurved), the laminal cells that are thick-walled with quadrate or rectangular lumina (seen in cross-section), and the wide and deep costa that has two bands of stereids.

KEYWORDS:

• Dawson Turner herbarium
• Dicranaceae
• lectotype
• mosses
• nomenclature

Acknowledgments

The careful morphological-anatomical observations and illustrations herein were made by the late Eva Maier (1928–2016). Her resolve, thoroughness, and attention to bryological detail, as well as her immense generosity, were and still are inspirational. The collaborative project was supported by Conservatoire et Jardin botaniques de la Ville de Genève (G) and the Natural History Museum, London (BM). The two anonymous reviewers are gratefully acknowledged for their comments on an earlier version of this manuscript. Fadil Adjva (G) scanned the original line drawings for Figure 2 that were done by Eva Maier.

Notes on contributors

Michelle J. Price Bryophyte herbarium curator in G, interested in historical collections and the valorisation of herbarium specimens. Specialist in the taxonomy of certain groups in the Dicranaceae and involved in bryophyte nomenclature.

Eva Maier Specialist in the taxonomy of the genus Grimmia Hedw. and a renowned bryophyte collector from Switzerland whose collections are now deposited in G.

Leonard T. Ellis Curator of the bryophyte herbarium in BM, with a special interest in bryological nomenclature and the taxonomy of the tropical moss family Calymperaceae.

ORCID

Michelle J. Price http://orcid.org/0000-0002-2706-1124