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Acarospora macrospora: Big Spore Cracked Lichen

Acarospora macrospora, commonly known as big spore cracked lichen, is a fascinating lichen species belonging to the Acarosporaceae family. This lichen exhibits a distinctive cracked appearance, especially as it ages, resembling dried earth.

This lichen is a symbiotic organism, often described as a "dual organism," formed through a partnership between a fungus and an alga.

Considerations for Pets

• The provided text indicates a "No" rating for safety with both dogs and children.
• The dry lichen thallus is brittle and may break into small fragments easily.

Considerations for Children

• The provided text indicates a "No" rating for safety with both dogs and children.
• The dry lichen thallus is brittle and may break into small fragments easily.

Taxonomy and Nomenclature

• Scientific Name: Acarospora macrospora (Hepp) Bagl.
• Common Name: Big Spore Cracked Lichen, American cracked lichen, Asahina's cracked lichen, California cracked lichen
• Kingdom: Fungi
• Family: Acarosporaceae
• Rank: Species
• Synonyms: Not explicitly provided in the text.

Distribution and Habitat

• Grows on exposed rock surfaces, walls and cracks in rocks.
• Found in open areas and areas with partial shade.
• Observed in southeastern Arizona, eastern UAE and northern Oman.
• Also found attached to brittle tree bark.

Morphological Characteristics

• Growth Habit: Lichenous.
• Structure: Lichen.
• Thallus can be "areolate," cracked into numerous individual sections.
• The thallus may have a white, cracked appearance with tiny white "mounds."
• Older lichens may exhibit a cracking center.

Ecological Role

• An early colonizer species.
• Fragments of the brittle thallus can break off easily, aiding in dispersal.

Spores

• Spores are produced in sacs (asci) in the fruiting bodies.
• The fungus disperses spores that must then meet with a compatible algae partner.
• Spores differ in size, smaller spores easily differentiate Acarospora macrospora from A. oligospora.
• Mature spores may be ornamented with irregular cracks.

Interactions with Other Organisms

• Lichens are symbiotic relationships between fungi and algae or cyanobacteria.
• Larger, more ancient lichen specimens support other range of organisms.
• Some lichen species are lichenicolous, meaning they grow on other lichens.

Quirky Facts

• Lichens are sometimes referred to as "dual organisms" due to their symbiotic nature.

Further Information

• BioLib.cz: http://www.biolib.cz/en/taxonsubtaxa/id164050/
• Lichen Gallery of Leif &amp Anita Stridvall.
• Rutgers NJAES: Tree-Dwelling Lichens.