In the Uredinales an aecium with a cornute peridium, thin at the sides, usually rupturing by longitudinal slits, and made up of characteristically marked and imbricated cells. The name is taken from the form-genus Roestelia. (Pl. roestelia.)
Found on
http://ppathw3.cals.cornell.edu/glossary/Defs_R.htm
In Gymnosporangium species it is an aecium with a strongly developed peridium extending beyond the chains of aeciospores.
Found on
http://www.encyclo.co.uk/visitor-contributions.php
No exact match found.
