Leocarpus fragilis (Dicks.) Rostaf.

Leocarpus fragilis (Dicks.) Rostaf.

Saturday 18th July 2020

Leocarpus fragilis is one of the most striking of slime moulds, with its clustered dark red to date brown sporocarps 1.5 - 2 mm high and 1.0 - 1.5 mm in diameter, looking like so many grape pips grouped together on a twig, or suspended from weak, slender and often branched yellowish stalks.

The shining ovoid or pyriform peridium fractures like an egg shell to expose the dark spore mass and the abundant pale yellow badhamioid lime-filled capillitium.

Through the microscope, the capillitium is seen to be predominantly lime-filled, with occasional limeless hyaline connecting threads. Main branches range from 5 to 15𝜇m in diameter.

Spores in mass are almost black, and dark brown in transmitted light, (10-)12-14𝜇m in diameter, spherical, and minutely warted.

The bright yellow plasmodium may sometimes be found emerging from the soil or creeping over moss and conifer twigs during the Autumn. The immature sporocarps are also yellow.

This unmistakeable species is common and widespread, usually associated with conifers.