Gowardia nigricans

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Gowardia nigricans, commonly known as the gray hair lichen or gray witch's hair, is a fruticose lichen in the Parmeliaceae family. It is currently listed as Secure.

Habitat and distribution
- Usually grows on soil, especially in tundra heath, but can also live on the low branches of trees or shrubs.
- In Canada it is found on Raft Mountain in Wells Gray Park, British Columbia.
- It also occurs in the South Orkney Islands of Antarctica, and has been recorded in Greenland and New Zealand.

Appearance
- The lichen has a shrubby, erect or tangled form.
- Its branches range in color from pale pinkish to nearly black, but always have black tips.
- The surface is generally dull, and large brown fruiting bodies (apothecia) can appear.

Chemistry and identification
- Standard chemical tests usually give: cortex and medulla PD+ yellow, K+ yellow, KC+ red, and C+ pink. Very dark specimens can be harder to read.
- It contains several chemicals, including alectorialic acid, barbatolic acid, alectorialin, and 5,7-dihydroxy-6-methylphthalide.

Ecology and research
- Alectorialic acid has been studied for potential antiviral properties.
- Growth is very slow. In grazing studies with reindeer in Svalbard, Gowardia nigricans showed about 2.43 mg per gram of lichen growth, roughly a 2.5% increase in mass over 10 weeks, indicating slow recovery after being eaten.
- Some research suggests it could be useful as an indicator species for monitoring air pollution.

Taxonomy
- The species was first described in 1810 as Cornicularia ochroleuca var. nigricans and later recognized as Alectoria nigricans before being placed in the genus Gowardia in 2009, with Gowardia nigricans as the type species.