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The other half
Field Mycology Volume 5(1), January 2004
THE OTHER HALF The telial stage of the rust fungus Gymnosporangium confusum A.W. and G.M. Brand 14 Bishopton Lane, Stratford on Avon, Warwickshire CV37 9JN
I
n the April 2001 issue of Field Mycology we reported the recent widespread occurrence in Warwickshire of the pycnial and aecial stages of the rare rust fungus Gymnosporangium confusum on Crataegus (hawthorn). G. confusum is one of the rust fungi which during its life cycle alternates between two different host plants. According to Wilson and Henderson (1966) the infections on Crataegus in early summer form aeciospores which are not capable of infecting this plant and instead infect Juniperus sabina. In spring infections on J. sabina produce telia containing teliospores. These produce basidiospores which infect Crataegus, Mespilus or Cydonia. A puzzle about our Warwickshire observations up to
the year 2000 was that we had failed to find the stage on J. sabina, although spreading and procumbent forms of this species are widespread in local gardens and amenity plantings. Since then we have found infections on such garden junipers. Spores of rust fungi are capable of spreading through the air for very many kilometres (Ingold, 1971). However the majority of spores are deposited close to the source, resulting in a steep gradient in infection frequency near to the source and a much shallower gradient at larger distances. During our survey of hawthorn infections in 2000 we detected a number of ‘hot spots’ where infections were abundant in comparison with those on bushes sometimes as little
Fig.1. Gymnosporangium confusum, groups of gelatinous telia hanging from the branches of Juniperus sabina. Also visible are the scars left behind when telia have dropped off (arrowed). Photograph © A.W. Brand.
14
Field Mycology Volume 5(1), January 2004 tion experiments with rust fungi (1889). He commented that Gymnosporangium spp. were very easy to cultivate and successfully infected seedlings of Crataegus, Cydonia (quince) and Mespilus (medlar) on several occasions by inoculation with germinating teliospores of G. confusum obtained from J. sabina near King’s Lynn. Following his methods we incubated teliospores from the Shottery site overnight in a few drops of water and used a camel hair brush to transfer germinating teliospores Fig. 2. A single telium of Gymnosporangium confusum on the underin water to the young leaves side of a twig of juniper. Photograph © A.W. Brand. emerging from opening buds of as 10m away, indicating the existence of local two potted hawthorn seedlings on 25 March sources. We were able to gain access to 2002. We kept a third seedling as a control search at four of our ‘hot spots’ in the spring brushed with water. These were covered in of 2001. At the end of April on wet days we polythene bags for two days and then kept found telia at each site on spreading garden together. Only the spore inoculations junipers. Groups of telia occurred on spindle resulted in pycnial infections after three shaped portions of twigs and when engorged weeks, followed later by aecia. with water the gelatinous telia were trianguThe evidence that G. confusum has been lar in shape and yellow with brown streaks completing its life cycle in the Stratford on (Fig.1). They readily dropped off leaving Avon area for at least several years is good. scars (Fig.1). Immature telia were small In addition to the occurrence of the aecial in Oxfordshire, Staffordshire, velvety brown protruberances which were stage difficult to find. The teliospores varied in Warwickshire and Worcestershire reported by wall thickness, from thick and brown to thin us in 2001, it has since been found in and hyaline, and had a length/width ratio of Herefordshire by Cherry Greenway and also 1.6 (brown) and 2.2 (pale). The other in Leicestershire and Northamptonshire but species of Gymnosporangium which forms there are no confirmed sightings elsewhere in aecia on hawthorn, G. clavariiforme, (Wilson Britain. So far there are no recent reports of & Henderson, 1966) differs not only in the telial stage outside Warwickshire. On the forming telia on a different host species, other hand the BMSFRD (2003) contains Juniperus communis, but also in having records made in the last ten years of the teliospores with a length/width ratio of 4.6 aecial stage of G. clavariiforme on hawthorn (brown) and 6.3 (pale). Telial infections of from widespread locations in England G. confusum were found on a wide age range (Devon, Durham, Norfolk, Shropshire and of juniper twigs from a branch 3cm in diame- Surrey) as well as from Ireland. Is ter with telia along a 5cm twig length down G. confusum really restricted to the western to an approximately 2 year old shoot midlands of England? Some of our observasupporting a single telium (Fig.2). tions may help in the search for it. Continued monitoring of the source at Shottery showed that at least some of the The peak time for aecia is June – July and the infected regions on the shoots formed telia in intensity of infection on hawthorn has varied between years. 2000 was a bumper year with every subsequent year. Plowright, who is the authority for the abundant infections on leaves and fruits name G. confusum, carried out many inocula- (photograph in Brand & Brand, 2001). At 15
Field Mycology Volume 5(1), January 2004 the Shottery hot spot there were few lesions in 2001 and 2002 and many infections on leaves in 2003. Infections on Mespilus (medlar) have been found each year and were up to 15mm across, much more conspicuous than those on Crataegus. In this midland area spring rain is usually intermittent and between 16 March and 19 May 2002 there were at least five occasions on which engorged telia were found on garden junipers. In between times the telia either fell off or dried up and at least some new telia matured and swelled up in each episode. Infections on garden juniper should be sought in March to May, in wet weather. 2004 might prove to be a good year for infection on the aecial hosts. Do you know a medlar near you? The best places to search are where J. sabina in gardens and an aecial host (medlar, infrequently clipped hawthorn hedges or ornamental Crataegus trees) occur side by side. This is usually in suburbia
amongst older gardens – not normal foraying country but somewhere which provides an opportunity for finding fungi during daily routine. You are urged to keep a look out for this and other Gymnosporangium species. Please keep specimens and tell us about your finds. There is still much to learn about Gymnosporangium in Britain. References Brand, A.W. and Brand, G. M. (2001) Have you seen this? A Warwickshire oddity. Field Mycology 2(2): 66-67. Ingold, C.T. (1971) Fungal Spores: their liberation and dispersal. Clarendon, Oxford. Plowright, C. B. (1889) A Monograph of the British Uredineae and Ustilagineae. Keegan Paul Trench, London. Wilson, M. and Henderson, D. M. (1966) British Rust Fungi. Cambridge University Press, Cambridge.
TAPINELLA PANUOIDES AND ITS VARIETY IONIPUS n a visit to Pembury Walks woodland, near Tunbridge Wells on October 23rd 2002, I noted several caps of Tapinella panuoides (= Paxillus panuoides) ringing several wellrotted Scots Pine stumps. I am more used to finding this on worked wood such as old railway sleepers and it has been recorded several times over the years on sleepers at Shorne Country Park, and Beacon Country Park, Kent.The only other recorded sites in Kent are Farningham Wood and Oldbury Hill. It was interesting to see that the bases of the caps were covered in a bright purplish tomentum, making this the variety ionipus. I collected one or two caps and when at home later that evening in artificial light, noticed that the purple colour had disappeared completely. I was surprised to see, in daylight the next morning, that the purple colour was obvious again. Perhaps this purple variety is much commoner than we think? Perhaps it even represents the typical condition but if observed under poor or artificial light the colour goes unnoticed?
O
Joyce Pitt 17 Church Road, Crockenhill Kent BR8 8JY
16
THE OTHER HALF The telial stage of the rust fungus Gymnosporangium confusum A.W. and G.M. Brand 14 Bishopton Lane, Stratford on Avon, Warwickshire CV37 9JN
I
n the April 2001 issue of Field Mycology we reported the recent widespread occurrence in Warwickshire of the pycnial and aecial stages of the rare rust fungus Gymnosporangium confusum on Crataegus (hawthorn). G. confusum is one of the rust fungi which during its life cycle alternates between two different host plants. According to Wilson and Henderson (1966) the infections on Crataegus in early summer form aeciospores which are not capable of infecting this plant and instead infect Juniperus sabina. In spring infections on J. sabina produce telia containing teliospores. These produce basidiospores which infect Crataegus, Mespilus or Cydonia. A puzzle about our Warwickshire observations up to
the year 2000 was that we had failed to find the stage on J. sabina, although spreading and procumbent forms of this species are widespread in local gardens and amenity plantings. Since then we have found infections on such garden junipers. Spores of rust fungi are capable of spreading through the air for very many kilometres (Ingold, 1971). However the majority of spores are deposited close to the source, resulting in a steep gradient in infection frequency near to the source and a much shallower gradient at larger distances. During our survey of hawthorn infections in 2000 we detected a number of ‘hot spots’ where infections were abundant in comparison with those on bushes sometimes as little
Fig.1. Gymnosporangium confusum, groups of gelatinous telia hanging from the branches of Juniperus sabina. Also visible are the scars left behind when telia have dropped off (arrowed). Photograph © A.W. Brand.
14
Field Mycology Volume 5(1), January 2004 tion experiments with rust fungi (1889). He commented that Gymnosporangium spp. were very easy to cultivate and successfully infected seedlings of Crataegus, Cydonia (quince) and Mespilus (medlar) on several occasions by inoculation with germinating teliospores of G. confusum obtained from J. sabina near King’s Lynn. Following his methods we incubated teliospores from the Shottery site overnight in a few drops of water and used a camel hair brush to transfer germinating teliospores Fig. 2. A single telium of Gymnosporangium confusum on the underin water to the young leaves side of a twig of juniper. Photograph © A.W. Brand. emerging from opening buds of as 10m away, indicating the existence of local two potted hawthorn seedlings on 25 March sources. We were able to gain access to 2002. We kept a third seedling as a control search at four of our ‘hot spots’ in the spring brushed with water. These were covered in of 2001. At the end of April on wet days we polythene bags for two days and then kept found telia at each site on spreading garden together. Only the spore inoculations junipers. Groups of telia occurred on spindle resulted in pycnial infections after three shaped portions of twigs and when engorged weeks, followed later by aecia. with water the gelatinous telia were trianguThe evidence that G. confusum has been lar in shape and yellow with brown streaks completing its life cycle in the Stratford on (Fig.1). They readily dropped off leaving Avon area for at least several years is good. scars (Fig.1). Immature telia were small In addition to the occurrence of the aecial in Oxfordshire, Staffordshire, velvety brown protruberances which were stage difficult to find. The teliospores varied in Warwickshire and Worcestershire reported by wall thickness, from thick and brown to thin us in 2001, it has since been found in and hyaline, and had a length/width ratio of Herefordshire by Cherry Greenway and also 1.6 (brown) and 2.2 (pale). The other in Leicestershire and Northamptonshire but species of Gymnosporangium which forms there are no confirmed sightings elsewhere in aecia on hawthorn, G. clavariiforme, (Wilson Britain. So far there are no recent reports of & Henderson, 1966) differs not only in the telial stage outside Warwickshire. On the forming telia on a different host species, other hand the BMSFRD (2003) contains Juniperus communis, but also in having records made in the last ten years of the teliospores with a length/width ratio of 4.6 aecial stage of G. clavariiforme on hawthorn (brown) and 6.3 (pale). Telial infections of from widespread locations in England G. confusum were found on a wide age range (Devon, Durham, Norfolk, Shropshire and of juniper twigs from a branch 3cm in diame- Surrey) as well as from Ireland. Is ter with telia along a 5cm twig length down G. confusum really restricted to the western to an approximately 2 year old shoot midlands of England? Some of our observasupporting a single telium (Fig.2). tions may help in the search for it. Continued monitoring of the source at Shottery showed that at least some of the The peak time for aecia is June – July and the infected regions on the shoots formed telia in intensity of infection on hawthorn has varied between years. 2000 was a bumper year with every subsequent year. Plowright, who is the authority for the abundant infections on leaves and fruits name G. confusum, carried out many inocula- (photograph in Brand & Brand, 2001). At 15
Field Mycology Volume 5(1), January 2004 the Shottery hot spot there were few lesions in 2001 and 2002 and many infections on leaves in 2003. Infections on Mespilus (medlar) have been found each year and were up to 15mm across, much more conspicuous than those on Crataegus. In this midland area spring rain is usually intermittent and between 16 March and 19 May 2002 there were at least five occasions on which engorged telia were found on garden junipers. In between times the telia either fell off or dried up and at least some new telia matured and swelled up in each episode. Infections on garden juniper should be sought in March to May, in wet weather. 2004 might prove to be a good year for infection on the aecial hosts. Do you know a medlar near you? The best places to search are where J. sabina in gardens and an aecial host (medlar, infrequently clipped hawthorn hedges or ornamental Crataegus trees) occur side by side. This is usually in suburbia
amongst older gardens – not normal foraying country but somewhere which provides an opportunity for finding fungi during daily routine. You are urged to keep a look out for this and other Gymnosporangium species. Please keep specimens and tell us about your finds. There is still much to learn about Gymnosporangium in Britain. References Brand, A.W. and Brand, G. M. (2001) Have you seen this? A Warwickshire oddity. Field Mycology 2(2): 66-67. Ingold, C.T. (1971) Fungal Spores: their liberation and dispersal. Clarendon, Oxford. Plowright, C. B. (1889) A Monograph of the British Uredineae and Ustilagineae. Keegan Paul Trench, London. Wilson, M. and Henderson, D. M. (1966) British Rust Fungi. Cambridge University Press, Cambridge.
TAPINELLA PANUOIDES AND ITS VARIETY IONIPUS n a visit to Pembury Walks woodland, near Tunbridge Wells on October 23rd 2002, I noted several caps of Tapinella panuoides (= Paxillus panuoides) ringing several wellrotted Scots Pine stumps. I am more used to finding this on worked wood such as old railway sleepers and it has been recorded several times over the years on sleepers at Shorne Country Park, and Beacon Country Park, Kent.The only other recorded sites in Kent are Farningham Wood and Oldbury Hill. It was interesting to see that the bases of the caps were covered in a bright purplish tomentum, making this the variety ionipus. I collected one or two caps and when at home later that evening in artificial light, noticed that the purple colour had disappeared completely. I was surprised to see, in daylight the next morning, that the purple colour was obvious again. Perhaps this purple variety is much commoner than we think? Perhaps it even represents the typical condition but if observed under poor or artificial light the colour goes unnoticed?
O
Joyce Pitt 17 Church Road, Crockenhill Kent BR8 8JY
16