Usnea (U. articulata)
Usnea articulata
Usnea articulata, also known as Old Man's Beard Lichen, is a distinctive lichen native to New Zealand. It is recognized for its long, beard-like strands and its role as an indicator of clean air and healthy forest ecosystems. This fascinating organism is neither plant nor fungus but a symbiotic relationship between algae and fungi. It forms long, hanging strands that resemble a beard, growing primarily on trees in humid forest environments. native trees
Image credit: Old Man's Beard Lichen (Usnea articulata). Wikipedia
Quick Facts
| Scientific Name | Usnea articulata |
|---|---|
| Height | Strands up to 30 cm (12 in) long |
| Spread | Forms tufts or beards, spreading across branches |
| Water Needs | Requires high humidity; absorbs moisture from air |
| Light | Filtered light to partial shade; avoids direct sun |
| Frost Tolerance | High; tolerates cold, but growth slows in freezing conditions |
| Salt Tolerance | Low; sensitive to salt and air pollution |
| Growth Rate | Slow; growth depends on air quality and humidity |
| Lifespan | Many years if undisturbed in suitable habitat |
Climate Suitability
| City | Suitability |
|---|---|
| Whangārei | Moderate |
| Auckland | Moderate |
| Hamilton | Moderate |
| Tauranga | Moderate |
| Rotorua | Ideal |
| Gisborne | Moderate |
| New Plymouth | Ideal |
| Napier | Challenging |
| Whanganui | Moderate |
| Palmerston North | Ideal |
| Wellington | Moderate |
| Nelson | Ideal |
| Christchurch | Challenging |
| Dunedin | Moderate |
| Invercargill | Ideal |
Growing
Substrate
Humidity
Light
- Epiphytic lichen found on trees and shrubs
- Prefers clean air and high humidity
- Sensitive to air pollution
- Does not require soil; absorbs nutrients from the air
Uses
- Indicator of clean air and healthy ecosystems
- Traditional uses in herbal medicine (antimicrobial properties)
- Occasionally used in natural dyes and crafts
Seasonal Characteristics
Spring
- Period of active growth
- May develop reproductive structures
- Absorbs moisture from spring rains
Summer
- Growth slows during dry periods
- May become dormant in very dry conditions
- Relies on morning dew and humidity
Autumn
- Growth resumes with increased rainfall
- Good time for observation and collection
- Colors may become more vibrant
Winter
- Continues slow growth in mild, wet winters
- Becomes dormant during freezing conditions
- Often most visible when deciduous host trees lose leaves
Observation and Conservation
Usnea articulata is best observed rather than cultivated:
- Photograph rather than collect when possible
- If collection is necessary for educational purposes, take only small samples
- Never harvest from protected areas or conservation land
- Support forest conservation efforts to protect lichen habitats
Planting Guide
Not typically cultivated; best left in natural habitats.
Propagation
Propagation is not recommended; Usnea articulata is best preserved in the wild.
Cultural History
Usnea articulata has been used by Māori for centuries for its medicinal and spiritual properties. The lichen was traditionally used to treat respiratory ailments, skin conditions, and as a natural remedy for sore throats. It was also believed to have protective powers against evil spirits and was often used in rongoā Māori (traditional Māori medicine) for its antimicrobial and anti-inflammatory properties.
In European traditions, Old Man's Beard Lichen was often used as a natural indicator of air quality and was valued for its ability to grow in areas with poor air quality. It was also used as a resource for natural dyes and as a material for fire-starting.
Cultural Significance
Usnea articulata is valued in Māori and European traditions for its medicinal and ecological roles. Its presence is a sign of healthy, undisturbed forests and is used in rongoā Māori (traditional medicine). It is also used as a bioindicator of air quality and as a resource for natural dyes and fire-starting.
Pests & Diseases
Generally pest-free; sensitive to air pollution and habitat disturbance.
Bonus Tip
Observe Usnea articulata in the wild and contribute to citizen science projects monitoring air quality and lichen diversity.
