Back to the Newsletter Contents and Home page

Lichens & Fungi

by Don Smith

I have to admit to very little field work in the past year apart from the ongoing churchyard surveying for lichens. In that respect St. Gregory’s Minster in Kirkdale is proving exceptionally species-rich and currently the list has increased to around 95 species, boosting the figure quoted in the last Newsletter.

Insofar as fungi are concerned I am grateful to Gill Smith who has given me a good list of species seen in the Gilling area. There are some 12,000 fungi recorded from the British Isles and this figure includes the lichen-forming fungi, Slime Moulds and yeasts but I shall just comment on three micro-fungi found in the garden. In late Autumn I found that the leaves of my raspberry canes had been attacked by a rust called Phragmidium ribi-idaei.

This showed as multitudes of extremely tiny (under 1mm) bright yellow-orange concave cups, at least a hundred a leaf in some cases. These are called uredinia, the structures which produce summer spores or urediniospores, sometimes called red- rust spores. As the year progressed these were replaced by black winter spores or teliospores, produced (needless to say) in telia: this is the resting phase designed to survive the winter. Attempting to unravel the complexities of all the sexual and vegetative reproductive life-cycles of these microfungi is, I am afraid, beyond me: I’ve come on to the scene far too late in life, I can manage summer urediniospores from uredinia and winter teliospores from telia but I shall be quite happy to give basidiospores, aeciospores and all the other parts of the life-cycles a miss. (These appear on one or more alternate host plants, to add to the complications. Ed)

Across from the raspberries are my redcurrants and blackcurrants and I noticed that the latter had got a white dusting of mildew on the leaves. Examination with a stereoscopic microscope revealed numbers of tiny fruiting bodies, each resting on a patch of brownish threads, the hyphae. Each fruit is known as a cleistotheclum, which means a fungal fruit with no apparent opening. Inside each will be one ascus (plastic bag) containing spores and so they belong to the Ascomycetes to which nearly all the lichens also belong. This fungus is the American mildew of gooseberry and currant, Sphaerotheca mors-uvae. Rose mildew and Peach mildew also belong to this genus.

Finally, over the last few years I have gathered up all the fallen leaves from the fruit trees and our beech hedges and emptied them into a two-metre square enclosure at the end of the garden which has already provided some rich, black loam. This year, for the first time, 1 noticed that many of the beech leaves at the surface were studded with white, chalky spheres. This was a slime mould called Physarum, probably Physarum cinereum.

I can recommend to readers four books relating to the matters discussed above, all of which are blessed with an abundance of excellent colour photographs. The first is an Illustrated Guide to Common Slime Moulds by Peter Katsaros, available from the Richmond Publishing Company Ltd. for £18.95. There are two illustrated books on lichens: Lichens on Trees by Commission Handbook No. 4 is entitled “Lichens in Southern Woodlands” and is priced at £4: it is available from HMSO bookshops or can be ordered. Perhaps the most exceptional and comprehensive book for those interested in what is to be found in their gardens is Stefan Buczacki’s Pests, Diseases and Disorders of Garden Plants published by Collins. With excellent text and colour photographs it is a snip at £20.

Back to the Newsletter Contents and Home page

© Ryedale Natural History Society 2001.
Page last modified 11th January 2001. Site maintained by APL-385