Plate 098 · hanging from a branch in the mist IdentificationFour marks on the plate
- 1Hanging, branched thallus, grey-green.
- 2Short fibrils along the sides of the branches.
- 3White, elastic central cord when a strand is stretched.
- 4On branches in cloud forest.
Easily confused with Cartilage lichenRamalina spp.Flattened branches with no central cord. Spanish mossTillandsia usneoidesA plant with grey scales and no elastic cord. 098 / 100 · FUNGI & LICHENS · PARMELIACEAENOT EVALUATED Beard lichen
Usnea sp.
Barba de piedra · Old man's beard
The grey-green beards hanging from branches in the cloud forest are lichens: a fungus and an alga living together. They take their water straight from the mist. Tucumán has several Usnea species, and telling them apart needs a lens and chemical tests.
- Length
- a few cm to over 20 cm
- Altitude
- c. 800 – 3,000 m
- Partners
- fungus + green alga
- Key feature
- elastic central cord
- Fruticose lichen
- Epiphyte
- Drinks fog
- Clean air
Altitude rangeWhere the mist never lifts
Most abundantRange in Tucumán Abundant in cloud forest and in alder and queñoa woodland, where mist wets the branches almost every day.
EcologyLives on air
- MistWater and nutrients from the air
- LightThe alga photosynthesises
- BranchesAlder, queñoa · support only
- BirdsUse it to line nests
It does not parasitise the tree, it only uses it for support. It is sensitive to air pollution, so plenty of it means clean air.
Life cycleTwo organisms in one
- Symbiosis. The fungus gives shape and shelter. The alga makes sugars from light.
- Revives with moisture. Dry, it turns brittle and dormant. Mist softens it and growth resumes.
- Spreads in fragments. Fragments and powdery granules holding both partners travel on the wind or with birds.
Where to look in Tucumán- Cuesta del Clavillo
- PN Aconquija
- Los Ñuñorcos
- Tafí del Valle (RP 307)
- Sierra de San Javier