Llanelli Naturalists Newsletter - March 2003 - No 69
Kath Cottingham

Leaders: Nigel Stringer and Dic Davies

A small group assembled in bright sunshine on the road bridge at the entrance to the Glan Gwenlais section of the Carmel Woods National Nature Reserve. Nigel introduced the meeting by talking about the importance of rusts whilst referring to a very useful handout listing the British species. Rusts are fungal plant parasites in the same group as toadstools, generally with rusty coloured spores, whereas mildews have pale or whitish spores and smuts have black spores and generally attack flowers. There are from two to five stages in the spore cycle of rusts (numbered 0 to IV) and stages II and III are most often seen on plants. Most rusts are host specific but species with the most number of stages may be seen on different plants for example stages 0 and 1 of Puccinia graminis are found on Berberis followed by stages II onwards on grasses or cereals. Rusts are very under recorded and only about 300 species have been recorded in the UK, 50 of which were on imported material. New rust hosts are being found continually and Nigel encouraged members to send plant material hosting rust to him for identification as the chances of making new records are very high. There are only six UK rust recorders in Britain and these include both Dic and Nigel,

The Welsh Rusts Database has been set up and maintained by Dic Davies, Nigel Stringer, Graham Motley and Ray Woods and during its seven years has amassed 8,000 records which is impressive when one considers that the total number of rust records for the UK is only 19,000. Rusts can be an aid to higher-plant identification as they may attack sub-species to different degrees.

The party then spread out to search for rusts along the road verges but rusts initially proved to be very elusive with several members hopefully showing rust-like marks to Nigel only to be told they were probably spider droppings! However we soon improved and during the afternoon found a number of different rusts.

The following rust species were found on the verges near the bridge and the banks of the Nant Gwenlais: Puccinia hordei on Holcus lanatus (Yorkshire Fog), Puccinia coronata on Arrhenatherum elatius (False Oat-grass), Melampsoridium betulinum on Betula sp. (birch), Puccinia coronata on Bromopsis ramosa (Hairy-brome) which is a new British Record for this host, Puccinia acetosae on Rumex acetosa (Common Sorrel), Puccinia lapsanae on Lapsana communis (Nipplewort), Pucciniastrum epilobii on Chamerion angustifolium (Rose-bay Willowherb), Phragmidium violaceum on Rubus fruticosus (bramble), Puccinia brachypodii var. brachypodii on Brachypodium sylvaticum (False-brome), Uromyces geranii on Geranium robertianum ssp. celticum (the limestone subspecies of Herb-robert) and Melampsora hypericorum on Hypericum androsaemum (Tutsan).  It is interesting to note that rust spore masses on ferns are usually white and this was shown by the two found here which were Milesina kriegeriana on Dryopteris dilatata (Broad Buckler-fern) and Milesina dieteliana on Polypodium vulgare (Polypody). Also found was an unidentified rust on Epilobium ciliatum (American Willowherb) which is a new host.

Higher-plants of interest were also recorded along these verges and included mostly calcicolous species such as Origanum vulgare (Wild Marjoram), Alchemilla sp. (a Lady’s-mantle), Clematis vitalba (Traveller’s-joy) and the Bromopsis ramosa already noted as a rust host. Richard Pryce also pointed out three plants of Pimpinella saxifraga (Burnet-saxifrage) and the hybrid rush Juncus × kern-reichgeltii with its parents J. effusus (Soft-rush) and Juncus conglomeratus (Compact Rush),

The party then entered the quarry area through the gate and on the open gravelly areas more rust species were recorded:- Puccinia graminis on Daclylis glomerata (Cock’s-foot), Coleosporium tussilaginis on Euphrasia nemorosa (Woodland Eyebright), Puccinia caricina var. ribesii-pendulae on Carex pendula (Pendulous Sedge) and Puccinia coronata on Festuca gigantea (Giant Fescue). At the southern end of the quarry two rust further rusts were noted: Melampsora euphorbiae on Euphorbia peplus (Petty Spurge) and Puccinia graminis subsp. graminicola on Briza media (Quaking-grass) which showed characteristic cracking on the stem. This is the 1st Welsh record and only the 3rd British record.

The higher-plants recorded from the open gravelly areas included Linum catharticum (Fairy Flax), Euphrasia nemorosa, Catapodium rigidum (Fern-grass), Carex flacca (Glaucous Sedge), Veronica montana (Wood Speedwell) and Alchemilla mollis (a lady’s-mantle). Plants growing on the limestone crags included Cotoneaster integrifolius (Small-leaved Cotoneaster), Solidago virgaurea (Goldenrod), Briza media, Asplenium trichomanes subsp. quadrivalens and Phyllitis scolopendrium (Hart’s-tongue) with a few Sympetrum striolatum (Common Darter) dragonflies here too. The pond near the quarry entrance was of interest as it supported a single clump of Triglochin palustre (Marsh Arrowgrass) and frequent stands of Equisetum fluviatile (Water Horsetail).

The group returned to the gate having spent a very interesting afternoon with Nigel and Dic who were thanked for their time and expertise. The meeting certainly changed my outlook on rusts – previously my reaction to a rust infested plant was, “What a mangy-looking thing’ but since that afternoon I look out for rusts and think, “Perhaps that’s a new host or even a new rust species; we’d better send a specimen to Nigel”!

Perhaps this is a good time to emphasise what I have long thought about Llanelli Naturalists’ field meetings which are not very well attended, presumably because they are not perceived as very exciting.  However over the years I have made the effort to attend most of them and generally they all turn out to be memorable in some way and often it is the ones that appear, beforehand, to be the least enticing that prove to be the best.. Just think, in attending a field meeting you are one of only about a dozen people in the whole world who will have had that experience! This calls for some Short Notes in the next issue about the most memorable finds and incidents, so any contributions from others would be very welcome.

Reference

Henderson D. M.  (2000).  A checklist of the Rust Fungi of the British Isles.  British Mycological Society