Lecanorales

(botany) An order of the Ascolichenes having open, discoid apothecia with a typical hymenium and hypothecium.

An order of the Ascolichenes, also known as the Discolichenes. Lecanorales is the largest and most typical order of lichens and parallels closely the fungal order Helo-tiales. The apothecia are open and discoid, with a typical hymenium and hypothecium. There are four growth forms—crustose, squamulose, foliose, and fruticose—all showing greater variability than any other order of lichens.

The Lecanorales is divided into 25 families, about 160 genera, and 8000–10,000 species. Family divisions are based on growth form of the thallus, structure of the apothecia, the species of symbiotic algae present, and spore characters. Species are separated by such characters as isidia, soredia, rhizines, and pores, and by chemistry. The larger families include: Cladoniaceae, Lecanoraceae, Lecideaceae, Parmeliaceae, Umbilicariaceae, and Usneaceae.