Minnesota Seasons - Star Rosette Lichen

Conservation • Description • Ecology • Distribution • Taxonomy


Conservation Status
IUCN Red List	not listed
NatureServe	NNR - Unranked
Minnesota	not listed

Photo by Alfredo Colon

Description

Star Rosette Lichen is widespread and common across the United States. It is very common in Minnesota, and has been recorded in 75 of the state’s 87 counties. It grows on the bark of elm and poplar trees and alder shrubs.

The vegetative body (thallus) is leaf-like (foliose), up to 1½″ in diameter, and divided into lobes. It sometimes merges with adjacent thalli, creating what appears to be one large thallus. It is attached to the substrate (bark) by pale anchoring structures (rhizines). The lobes are truncate at the tip can be 1 ⁄64″ to 1 ⁄16″ (0.5 to 1.5 mm) wide, but are usually no more than 1 ⁄64″ (0.5 mm) wide. The upperside is whitish-gray to cream-colored, usually darker in the center and paler at the margins. The surface has neither powdery dull granules (soredia) nor shiny granules (isidia). The underside is white to brownish.

Disk-like, spore-producing structures (apothecia) are usually abundant. The disks are 1 ⁄64″to ⅛″ in diameter, dark brown, and shaped like a plate. Each disk has a thick ring of tissue around it that resembles the tissue of the vegetative (non-fruiting) part of the lichen. The disks turn gray when dry.

Similar Species

Ecology

Substrate

Trees

Growth Form

Foliose

Habitat

Hosts

Elm, poplar, and alder


Distribution
		Sources 4, 7, 24, 26, 29, 30, 77, 81.
4/30/2024

Occurrence
Widespread and very common


Taxonomy
Kingdom	Fungi (fungi)
Subkingdom	Dikarya
Phylum	Ascomycota (sac fungi)
Subphylum	Pezizomycotina
Class	Lecanoromycetes (common lichens)
Subclass	Lecanoromycetidae (shield lichens, sunburst lichens, rosette lichens, and allies)
Order	Caliciales
Family	Physciaceae (rosette lichens, frost lichens, and allies)
Genus	Physcia (rosette lichens)
Mycobiont	Physcia stellaris
Photobiont

Subordinate Taxa


Synonyms


Common Names
Immaculate Rosette Lichen Star Rosette Lichen

Glossary

Apothecium

An open, disk-shaped or cup-shaped, reproductive structure, with spore sacs on the upper surface, that produces spores for the fungal partner of a lichen. Plural: apothecia.

Foliose

Adjective: Leaf-like growth form; referring to lichens with leaf-like growths divided into lobes.
Noun: The leaf-like, vegetative body of a lichen (thallus) that has thin, flat lobes which are free from the substrate.

Isidium

An asexual reproductive structure of a lichen consisting of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont) and enclosed within a layer of protective tissue (cortex). Plural: insidia.

Rhizine

A root-like structure of a lichen that attaches the lower layer to the substrate.

Soredium

An asexual reproductive structure of a lichen in the form of a tiny dull granule on the thallus surface that can be easily brushed off. It consists of a cluster of algal cells (the photobiont) wrapped in fungal filaments (the mycobiont), but without an outer layer of protective tissue (cortex). Plural: soredia.

Thallus

The vegetative body of a lichen composed of both the alga and the fungus. Plural: thalli.


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Luciearl


The lichen colors pop out after it rains. I don't think I'be seen pink before but found tiny amounts on several branches.


Alfredo Colon


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