ETYMOLOGY: From the host plant.

NOTES: Several rusts, including species of Coleosporium, Miyagia, and Puccinia, have been described or recorded from Sonchus, but only one rust, the widespread Miyagia pseudosphaeria (Mont.) Jørst., has been recorded in New Zealand on Sonchus (Cunningham 1924). Puccinia embergeriae is quite distinct from M. pseudosphaeria, which is distinguished by possessing a peripheral, palisadelike layer of brown, thick-walled paraphyses in both the uredinia and telia; such paraphyses are lacking in P. embergeriae. In addition, the urediniospores of M. pseudosphaeria are generally narrower, with 3- 4 germ pores. Parmelee & Savile (1981) gave an account of North American Puccinia species on members of the Lactuceae (syn. Cichorieae). Of the species treated, P. hieracii, which has been recorded in New Zealand, has a wide host range within the Lactuceae. However, the urediniospores of P. hieracii have a tonsure, or smooth area, below each germ pore, a feature not observed in P. embergeriae.

Embergeria grandifolia is a threatened plant, and is listed as a nationally endangered species i Hitchmough (2002). Puccinia embergeriae, which is an obligate parasite, probably co-exists with its host plant. However, it is also a threatened species, classified as nationally critical (Hitchmough 2002).

When viewed with the scanning electron microscope, the urediniospores of P. embergeriae appeared to be smaller than when viewed by light microscopy. Measurements were checked and it is concluded there is significant shrinking of these spores when placed in the electron microscope. At high magnification, wrinkling of the spore surface between the spines was evident.