Phomopsis (Sacc.) Bubák
(a form genus of coelomycetes)

A common form genus of coelomycetes forming black pycnidia immersed in (usually) dead stems. The pycnidia produce simple conidia, on distinct conidiophores. These conidia usually contain two oil-droplets.

Some species also produce filiform, curved, sinuate or hooked, B-conidia (sometimes only late in the season) which are much longer than the A-conidia above.

Many of the species are host limited (or at least there are different names which have been applied to Phomopsis on different hosts).

Phomopsis are the imperfect stages of Diaporthe sl.

Coelomycetes with very thick-walled, erumpent pycnidia with bases persisting as little black cups after the top half has been lost. The conidia have distinct conidiophores. Mostly on dead stems or peduncles.

Some species form brown or black halos in the surrounding epidermis.

The very similar Phoma produces slightly smaller and thinner-walled pycnidia but is best distinguished by the absence of conidiophores.