Christmas ornament cecidology

This gorgeous gall was like a Christmas ornament on the south Oslo Riverfront Conservation Area scrub. This gall (or cecidia) on Faey’s palafoxia (Palafoxia faeyi) was caused by a gall-making midge (Asphondylia sp.). Note the exit hole below …

A Florida scrub endemic, Faey’s palafoxia — and this associated gall — has become more abundant (or evident) since the property was roller-chopped last year. This slightly woody wildflower grows to be from 2 to 6′ tall and has rough, tough leaves.

This plant is a member of the Asteraceae (daisy) family, and its white or pinkish floral heads are composed entirely as ‘disc’ flowers (i.e., no petals).

Plant gall-maker relationships are quite specific, and the gall-making midge associated with Faey’s palafoxia uses the floral heads. Note the green gall beginning to form at the left back side of this photo …

We have just engaged in some Christmas cecidology, the study of galls.