Stigmidium ascophylli (Cotton) Aptroot

Unlichenized endosymbiotic marine Ascomycota

    Hyphae developing inside the host tissues (endosymbiotic) only visible to the naked eyes owing to the minute black dots (pseudothecia) on the fertile bodies of the host cortex surface. Ascii 8-spored with a thick apex, I-. Ascospores oblong with truncated ends, 1-septate, 15-23 x 4,5-6 µm. This species is visible but common only on the fertile bodies of its hosts: Pelvetia canaliculata and Ascophyllum nodosum.

_ Not to be confused with Collemopsidium pelvetiae of which the perithecia are much larger and not distributed on the host fertile sections.

N.B. Forms a mycophycobiosis ("inverted lichen"), that is to say a symbiosis between a microscopic fungus and an alga which is the dominant partner.