Uninfected leaf under surface - magnified

Descrission:

Longitude (deg): -1.5. Latitude (deg): 53.3. Longitude (deg/min): 1° 30' W. Latitude (deg/min): 53° 20' N. Vice county name: South-west Yorks. Vice county no.: 63. Country: England. Stage: Infection. Associated species: Alnus glutinosus. Identified by: Malcolm Storey. Comment: on Alder leaf. Other taxa shown: The yellow objects are leaf glands. Category: macro-photograph. Image scaling: magnified. Photographic equipment used: Canon EOS400D dSLR and MP-E 65mm x1 to x5 macro lens.