The Fern Gazette Volume 20 Part 6

Published 2nd November 2017

Edited by M. Gibby & A. Leonard


Silurian-Devonian origins of ferns and lycophytes – what we know, what we need to find out
P.G. Gensel pg(s) 217-242
This represents a synopsis of current knowledge of the Siluro-Devonian fossil record concerning evolution of lycophytes and ferns. This is the time period when several taxa or lineages at different grades of organisation existed that may be informative about the origins of these groups or structures typical of these groups. Considerable new data, including earlier first appearances of lineages and plant structures, new data about Siluro-Devonian lycopsids or basal euphyllophytes, and new whole plant reconstructions of small to tree-size plants in both lineages, have been published in recent years. It is not possible to be completely comprehensive, but the taxa discussed are either central to established ideas, or provide new information in relation to phylogenetic relationships and evolutionary trends. It remains difficult to trace the phylogenetic relationships of early plants relative to extant lineages. New data are reviewed which may be important in reassessing homology of characters and/or hypotheses of such relationships or in determining which taxa to exclude. Including fossils in estimates of relationships of these major lineages of plants will provide a more accurate and comprehensive understanding of the past history of seedless vascular plants.

A short biography of the author pg(s)243-244


A new record of brown rot disease in water fern Azolla microphylla (Azollaceae): loss of important bio-resource
S. Dey, M. Hore, J. Biswas, M. Biswas, B.K. Mandal, P. Das & S. Gupta pg(s) 245-254
Severely infected water fern, Azolla microphylla Kaulf., has been observed in natural habitats in different districts in the lower Gangetic plain of West Bengal, India. The infected plants have turned dark brown and been rotted entirely within 5-7 days, causing loss of natural resource as the plant species has immense commercial value. Specific growing colonies with cottony white mycelium, yellow pigmentation on the cultured medium, macro- and micro- conidial features, and absence of chlamydospore indicate the causal pathogen to be Fusarium thapsinum Klittich., Lesile, Nelson, Marases. The identification of the causal pathogen has been authenticated by standard pathogenicity test (Koch’s Postulates). Extensive literature survey reveals that this is a new record of brown rot disease in A. microphylla.

Cystopteris fragilis subsp. huteri, a taxon new to the British Isles and related taxa in the Cystopteris fragilis complex: Cystopteridaceae (Polypodiopsida)
D.J. Tennant pg(s) 255-266
A taxon in the Cystopteris fragilis (L.) Bernh. complex that occurs in Britain appears up to now to have been overlooked there. It is proposed that this fern, which was recently rediscovered in Snowdonia, North Wales, should be referred to a subspecies of C. fragilis, namely subspecies huteri (Hausm. ex Milde) C. Prada & Salvo, that occurs in mainland Europe, but had not previously been recognised in the British Isles. The Snowdonia fern is distinct in its morphology from other British taxa in the C. fragilis complex and is described here together with its historic records and present distribution, updated from information given in an earlier paper in Watsonia (Tennant, 2010), and its relationship to affiliated taxa is discussed.

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