GALL FORMING FUNGI
 
When I saw plant galls for the first time I wanted to know what species there were to be found basically, and so I started collecting anything that looked like a plant gall. Boxes full of them I have now. Nowadays I think it is better for me to take pictures (digital or slides) and when you are interested in the gall maker itself, it is a good idea to try to get the inhabitants to emerge from the galls. The list of species described below are gall makers and their hosts, from species that I myself or another gall studying person has seen. A description is given and, were possible, a picture. For people who are interested in the Dutch distribution of pant galls can soon take a look at the database we are preparing for this website. Since the subject of plant galls becomes more popular only recently, we do not have yet such an extended database. Any contribution is welcome!
 
Albugo candida is a fungus that causes thickening of all parts of  Capsella bursa-pastoris and white colouration of these thickened parts. It mostly occurs on the stem. The flowers remain on the plant and the fruit becomes deformed.  
   
Claviceps purpurea is a fungi that can be often found on grasses. They are rather common on Lolium perenne and Phleum pratense (Timotee grass). The fruit bodies stick out of the flowers like black sticks and when you see them on Spartina, they are slightly bend, like bananas, and quite a lot bigger.

     
Exobasiudium juelianum is one of the Exobasidiums mainly occuring on Ericaceae. This species is very particulair for Vaccinium vitis-idae. The top leaves of a branch because deformed by the fungus and coloured white-pink and sort of powdery. Rare.  

     
Exobasiudium vaccinii is also only occuring on Vaccinium vitis-idae. The difference with the previous species is the fact this species looks like a "gall apple" in stead of a bunched lot of thickened leaves like E. juelianum.  
Picture: S. Visser
   
Gymnosporangium cornutum I first found in the Pyrenees and in Norway on Sorbus aucuparia. The swellings are orange and can be found on the top of and underneath the leaves and on the leaf stems petioles. Swellings are especially visible on the lower surface and show aecidia.

(picture: P. Koster)
   
Puccinia coronata on Rhamnus frangula at Suameer, Friesland. These pictures show the fungus in its full glory, when the colors are most spectacular. One week later, a friend showed me a specimen that was already turning more orange and brown. The galls are a few centimeters in length and covered with aecidia. They occur on the tops of young branches and leaves in May and June. The funges migrates to grasses.

(Pictures: B. Kabbes)
 
Taphrina alni is a fantastic and rather common species of fungi on Alder (Alnus glutinosa). The gall developes (in the female catkins) from the ovary and emerges from between the outer scales like a flat shaped elongated flag with a hard and slightly shiny surface. The surface is smooth, lacking any hairs. The outer edges are rounded and the end is more broadened than the foot of the 'flag'. Early in the season the flag is fresh and green, but soon the colours start to vary from pale green to yellow, pink, red, purple and orange-like. Later the galls turn brown or more black and remains on the tree for a long time (until the next season).

(Picture: B. Kabbes)
 
Taphrina padi is to be found on Prunus domestica and Prunus spinosa. The fruits become swollen and deformed like an aubergine and turn from green to white to brown.

(Pictures: H. Slegten)

   
Triphragmidium ulmariae is a bright orange red coloured fungus on Filipendula ulmaria. The leaves are twisted and contorted, bearing bright orange red aecia.  
   
Urocystis syncocca (hepaticae-trilobae) forms flat and circular swellings on top of the leaf of liverleaf (Hepatica nobilis) that break open to release black powdery spores. The galls on the picture are found at Santa Cruz de la Serós, at Punta dÁuguasalient on approximately 1500 m above sea level, in Spain. According to Redfern (et al. 2002) it is a rare species that can also grow on the stems and petioles of liverleaf.


picture below: habitat of the fungus
(Pictures: Bauke Koole)

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