Aecidium magellanicum

{{Short description|Species of fungus}}

{{Speciesbox

| image = Aecidium_magnellanicum.jpg

| image_caption = Calafate rust growing on the shrub Beriberis microphylla in Chile.

| genus = Aecidium

| species = magellanicum

| authority = Berk. (1847)

}}

Aecidium magellanicum, commonly known as the calafate rust, is a species of rust fungi. This fungus can cause a growth defect known as a witches broom, an excessive growth of stems from a single point on a branch. The species is known to infect the evergreen shrub Berberis buxifolia in Argentina and Chile.Hernández JR, Hennen JF. (2003). [http://www.mycologia.org/cgi/content/full/95/4/728 "Rust fungi causing galls, witches' brooms, and other abnormal plant growths in northwestern Argentina".] Mycologia 95(4): 728–755.