The Fern Gazette Volume 19 Part 8

Published 8th November 2014

Edited by M. Gibby & A. Leonard


Bracken and the glassmaker’s art
C.M. Jackson pg(s) 281-294
Medieval and post-medieval documentary evidence records that glass could be manufactured using fern ash as a source of glass making alkali. This paper reviews the evidence for the use of bracken, the most abundant species of fern found in Europe, for glass manufacture by examining these early documentary sources and reviewing the contemporary archaeological evidence. Testing the viability of using bracken in glass manufacture by examining bracken growth patterns and yields, and its ability to form glass readily and produce a good quality product are reviewed and demonstrated through experimental investigation.

A short biography of the author pg(s)295


Monitoring change in Isoetes histrix Bory (Isoetaceae) at its northern distributional limit
D.A. Pearman, F.J. Rumsey & I.J. Bennallick pg(s) 297-306
A re-survey of the threatened Land Quillwort (Isoetes histrix Bory) at its northernmost range extent on the Lizard peninsula, Cornwall, indicates a massive decline (>90%) in total population size since 1982 with the loss of several major sub-populations. The factors responsible for this are considered and climatic changes, particularly in the pattern of rainfall, and management practices, such as the reduction in grazing, are implicated in its decline.

In vitro propagation and cryopreservation of the endangered filmy fern,
Trichomanes punctatum subsp. floridanum (Hymenophyllaceae)
V.C. Pence pg(s) 307-317
In vitro methods were investigated as a tool for propagating and preserving tissues of the endangered filmy fern, Trichomanes punctatum subsp. floridanum. Wild-collected sporophytes were grown ex situ in soil and were used as a source of material for establishing in vitro cultures. Gametophytes, germinated from spores, were grown and propagated on agar plates, but were not successfully surface sterilized for in vitro growth. Sporophyte cultures were successfully cryopreserved using the encapsulation-dehydration method and showed good survival through both drying and freezing. Tissues up to 24 months old survived cryopreservation, although the percentage of tissue pieces surviving was lower than with younger tissues. Older tissues also had lower levels of total soluble carbohydrates. Pre-culture of sporophytes for two days on ABA did not affect survival compared with pre-culture on medium lacking ABA. However, younger tissues lacking any pre-culture showed reduced survival through cryopreservation compared with pre-cultured tissues. These results demonstrate that in vitro propagation methods could be used to provide plants for restoration, while cryopreservation could play a role in the ex situ conservation of T. punctatum subsp. floridanum.

Hybridization in Polystichum (Dryopteridaceae: Pteridophyta)
A. Sleep† pg(s) 319-341
The origins of two European Polystichum species, tetraploids P. aculeatum and P. braunii, have been investigated through experimental hybridization with other Polystichum species from Europe and North America, and an attempt made to re-synthesize P. aculeatum from its putative diploid parents, P. lonchitis and P. setiferum. The results of the hybridization programme were unexpected. Hybrids between parents which were thought to be unrelated proved easy to synthesize, and showed bivalent formation at meiosis, and chromosome pairing occurred in all hybrids examined. The degree of pairing appeared to be similar regardless of the level of ploidy. This interesting phenomenon has still not been found to occur in any other fern genus and appears to be characteristic of Polystichum.


Oreogrammitis setosa and O. sinohirtella in Thailand
B. S. Parris pg(s) 296

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