Hooded Sunburst Lichen

IUCN Red List

NatureServe

Minnesota

not listed

Very common and widespread

Bark of deciduous trees

Hooded Sunburst Lichen is a widespread and very common lichen. It occurs throughout Europe and across North America. It is very common in Minnesota. It grows on bark on the trunks of deciduous trees in humid to moderately dry conditions. It rarely grows on rock or on detritus on the ground. It forms rosettes ¾″ to 1½″ in diameter that are bilaterally symmetric. Adjacent rosettes often fuse together into large colonies.

The vegetative body (thallus) is leaf-like (foliose) and divided into small branches (lobes). It grows closely or loosely attached to the substrate (wood or bark) but does not have root-like structures (rhizines). The lobes are flat to convex, rounded to straight across (truncate) at the tip, and 1 ⁄32″ to 1 ⁄16″ (0.8 to 2.0 mm) wide. The upper surface is smooth to shiny and deep orange where exposed to the sun, orangish-red to reddish-orange in partially shaded areas, and pale greenish-yellow in deep shade. Tiny reproductive structures (soralia), appearing as horizontal, crescent-shaped slits, are formed on the margins at the tips of the lobes. The soralia produce powdery, greenish-yellow clusters of cells (soredia). The soredia are dispersed by wind and rain, and can form new rosettes when they land on a suitable surface. The lower surface of the thallus is white to yellow and somewhat wrinkled. Rarely there are short, white, peg-like structures (hapters) attaching the thallus to the substrate.

Disk-like, spore-producing structures (apothecia) are rarely produced. When present, the disks are stalked, orange, up to ⅛″ (2.5 mm) in diameter, and shaped like a plate. They are smooth at first but often become rough and develop a ring hairs on the margin. Each disk has a ring of tissue around it that resembles the tissue of the thallus.

Sources: 4, 24, 26, 29, 30, 77.

Taxonomy
This species was originally named Physcia fallax in 1858. In 1860 it was moved to Xanthoria fallax, in 2002 to Xanthomendoza fallax, and in 2003 to Oxneria fallax. Today, many sources continue to use Xanthoria fallax, but most now use Xanthomendoza fallax. Few use Oxneria fallax, though Index Fungiforum does, and that should be the last word (or at least the current word) on the subject,.

Location: Woodbury, Minnesota