Diplotom hedi4462f.jpg

Diplotomma hedinii, ascospores, mounted in water, showing the care required with interpretation of septation if a more aggressive mountant is not used. The ascospores are strictly 3-septate but the inclusions within the cells can sometimes cause an illusion of a longitudinal septum. The arrow indicates one such 'false septum', one third of the way across from the left edge of the spore. Mounting in K, or better still, nitric acid is recommended.