Description contributed by Graham Kinsey, CABI.
Anamorph: Phomopsis sp. Conidiogenous cells 12-20 x ca 1 µm. Alpha-conidia 7-10 x 2-3 µm.
Teleomorph: stromata nearly invisible at first, no blackening of the substratum when young and immature, ostioles barely visible as minute black dots, surface of substrate later becoming ± blackened over wide areas. Ascomata 240-400 x 160-240 µm, scattered singly or sometimes crowded, usually rather deeply immersed within the pith with barely emergent papillate ostioles or emergent cylindrical, conical or rarely somewhat elongated necks. Peridium 20-30 µm thick. Ascomatal cavity filled with numerous broad, paraphysis-like hyphae when young. Asci 40-50(-85) x 4-7(-10) µm. Ascospores (9-)11-15 x 3-4(-5) µm, narrowly ellipsoidal to fusiform, usually 3-guttulate, possibly sometimes with short delicate appendages.
Diaporthe inquilina also occurs on umbellifers but produces a ventral zone line and has ascospores which become 1-septate and are usually 4-guttulate even before the septum has formed.
Preliminary molecular data provided by Castlebury et al. (2003) suggest that this species, the type of the genus Diaporthopsis, clusters within Diaporthe. The latter genus is in desperate need of a comprehensive modern monographic treatment, and recent changes in nomenclatural rules may mean that the anamorph name Phomopsis is preferred for these fungi.
On dead stems of Apiaceae (umbellifers) including Angelica, Anthriscus, Heracleum and Oenanthe.
From England (South Devon, Leics, Isle of Man, Middlesex, Northants), Ireland (Antrim, Dublin, Wicklow), Scotland (Clyde Isles, Mid & North Ebudes, Wigtowns) and Wales (Pembs).