Rhytismatales

Rhytismatales is an order of fungi belonging to the Ascomycota. These fungi are characterized by their prominent, dark, often erumpent stromata, which are specialized fungal structures that develop within or beneath the host tissue. The stromata are typically leathery and black, containing the ascocarps, which are the spore-producing structures. Within the ascocarps are the asci, sac-like structures that contain the ascospores. Rhytismatales are primarily plant pathogens, affecting a wide range of woody plants, including conifers and broadleaf trees. They are known to cause various diseases such as needle cast diseases, tar spot diseases, and leaf blights. The life cycles often involve overwintering in infected plant material, with spores being released and disseminated in the spring or summer. Reproduction can be sexual or asexual, with the sexual stage typically occurring within the stroma. Commonly encountered genera within this order include Rhytisma, Lophodermium, and Cyclaneusma, each with specific host preferences and disease symptoms. The economic impact of Rhytismatales can be significant, particularly in forestry and horticulture, where they can lead to reduced growth, defoliation, and increased susceptibility to other stressors in host plants.