The fifth taxonomic workshop was held on Saturday, 11 November in the Botany Department of the University of Leeds, and was followed on Sunday, 12 November by a field excursion to the Hebden valley and Hardcastle Crags near Hebden Bridge in the metropolitan district of Calderdale (v.c. 63).
Some fifteen members attended the workshop session in the University, and heard first Dr. M. E. Newton discuss the problems of sterile Brachytheciaceae. Dr. Newton gave hints on distinguishing species which might be confused with this family, and stressed the importance of the nerve projection on the dorsal side of the leaves of Eurhynchium spp. as a character separating them from their former congeners now placed in Rhynchostegium and Rhynchostegiella. Advice was given on the problems of several groups of superficially similar species within the family. After lunch, Dr. A. J. E. Smith outlined some important key characters helpful in the identification of Schistidium, Grimmia, Bryum, Mnium and Plagiothecium spp. During both morning and afternoon much useful work was done and many ideas swapped as members examined specimens under the microscope.
All are indebted to Prof. H. W. Woolhouse for permission to use the facilities of the Botany Department, to Dr. D. Bartley and Mr. G. A. Shaw for their invaluable assistance in making arrangements at the University, and to Dr. Newton and Dr. Smith for so readily giving us their time and advice.
Eleven enthusiasts gathered on an overcast morning to examine the bryophyte flora of Hardcastle Crags. This well-known beauty spot may justifiably be described as the best remaining locality for bryophytes in the much urbanised vice-county of South-West Yorkshire. The Hebden Water cuts a deep north-south gorge in the millstone grit moorland, and exhibits the characteristic southern Pennine clough flora, generally calcifuge but with local basicolous elements. The locality was well known to the Todmorden botanist John Nowell, who discovered Atrichum crispum here in one of its earliest sites.
On banks by the small stream and in adjacent pasture below the Greenwood Lee car park were found Nardia geoscyphus, Sphagnum russowii, Pohlia lutescens* and P. lescuriana*. Inside the woods, the party descended via the main track and observed en route Schistostega pennata in a hollow among gritstone on the trackside bank, Dicranodontium denudatum covering an old log, and fine Scapania umbrosa on the damp blocks of a wall and some old steps. On the rocks in and by the river, Atrichum crispum and Marsupella emarginata were among the species noted, with Sphagnum quinquefarium on a nearby bank. Eventually the river was crossed and the party reached the streamlet where Jubula hutchinsiae was discovered by James Needham in 1896. Many members were surprised to see that most of the material here is fully aquatic, its glaucous tufts clearly distinct from the accompanying Chiloscyphus. Several small patches were seen, but the species can scarcely be described as abundant, as it has been on previous occasions.
[* = New vice county record]
The next area visited was the riverside cliffs north of Gibson Mill. These produced, inter alia, Saccogyna viticulosa, Tetrodontium brownianum, Seligeria recurvata. Biindia acuta, Gymnostomum aeruginosum, Amphidium mougeotii, Bryum sauteri* and Heterocladium heteropterum. However, owing to a torrential downpour and very poor light conditions, some species known to occur here were missed, including Lejeunea lamacerina, Bartramia ithyphylla and Isopterygium pulchellum. Nowellia curvifolia was a nice find on logs here in the home country of its eponymous finder.
By now only five of the original group remained, their optimism rewarded by some improvement in the weather. There was no time to investigate the upper reaches of the gorge (with Andreaea crassinervia and Mylia taylori), nor the Blake Dean area, where a little Solenostoma caespiticium had been seen three weeks earlier by the local secretary. Instead the party ascended the east bank, where one member was sufficiently lynx-eyed in the gathering gloom to spot Bazzania trilobata*, the first v.c. record this century and confirmation of an old record. The final stop of the day was at a small but remarkable outcrop of calcareous grit, whose bryoflora was in total contrast to the adjacent and typical millstone grit. The principal species were Lejeunea cavifolia, Cololejeunea calcarea, Fissidens cristatus, Tortella tortuosa, Schistidium apocarpum, Zygodon viridissimus var. stirtonii, Neckera crispa, Homalothecium sericeum and Ctenidium molluscum.
The final ascent from the woods was made in gale-like conditions with driving rain; the clouds and dusk descending among the trees gave an aspect of wilderness to the gorge below. Yet few of those present could have failed to observe the effects of atmospheric pollution. Those optimistically scrutinising old elder found only a limited community dominated by Orthodontium lineare; the once rich epiphytic flora, including Ulota drummondii, collected in 1834, has long been extinct.
T. L. Blockeel