Smut
The name given to a group of Fungi which grow among the tissues of the stamens, ovaries, and leaves of many plants, but especially infest the Cereals (e.g., Barley and Oats) and other grasses. The scientific name of the group is Ustilaginei (from ustus, scorched), and refers to the scorched appearance of ears of Corn, or of other parts of plants, infested with the Fungi. The name Smut also refers to the dirty, sooty aspect of the Fungi. In the early stages, they consist of interwoven masses of mycelium, the threads of which bear numerous spores, either in a group on the tip of each thread, or singly on slender branches along their sides, near the tips. The spores vary a good deal in the different genera, some being one celled, others made up of cells grouped together to form a rounded mass, each cell in which may be fit to produce a new plant, or only the central cell may be fit to do so, the outer ones being sterile. In most of the species, the spores are more or less deeply coloured, and in the typical Smuts they are dark brown individually, and sooty-black when in masses. The outer tissues of the host-plant are usually torn open by the pressure of the ripening spores, and the dark, powdery masses of spores are displayed and become very conspicuous. It does not fall within the scope of this work to discuss the Smuts that attack grasses, serious though their effects frequently are. Few flowering plants are liable to much injury from the Fungi of this group. Ustilago violacea destroys the anthers of a good many species of Caryophylleae, e.g., Dianthus Carthusianorum, D. superbus, Saponaria officinalis, various species of Silene, &c.; the spores are one-celled, roundish, and pale violet. Sorosporium has the spores formed each of a mass of several equal cells. S. Saponariae distorts the anthers of the same Carophylleae as U. violacea; S. hyalinum consumes the seeds of Astragalus glycyphyllus, of a few other Leguminosae, and of Convolvulus sepium; S. primulicolum lives on young seeds of Primula elatior, P. farinosa, and P. vulgaris, destroying them, but showing no sign on the exterior of the ovaries. Urocystis has spores like those of Sorosporium except in the outer cells being smaller and sterile, the inner larger and fertile; U. Violae causes large swellings in the stalks and blades of the leaves, and in the stolons, of Viola odorata; U. Anemones causes similar swellings on various species of Anemone and other Ranunculaceae; U. sorospoides covers the leaves of Thalictrum minus with dark patches of spores.
Remedies cannot be employed owing to the Fungi growing inside the tissues of the host-plants. The affected plants ought to be removed and burned, to prevent the spread of the disease.