MelanconialesMel`an*co`ni*a"les\, n. pl. [NL., fr. Melanconium, name of the typical genus, fr. Gr. ? black + ? dust, in allusion to the dark spores.] (Bot.) The smallest of the three orders of Fungi Imperfecti, including those with no asci nor pycnidia, but as a rule having the spores in cavities without special walls. They cause many of the plant diseases known as anthracnose.