The species is quite unique within the genus by the 3-septate ascospores.
Why suggested for a Global Red List Assessment?
Dimelaena triseptata is an endemic lichen from Saint Helena. It grows on open soil and is threatened by increasing trampling by tourists and by getting overshadowed by the invasive plant Carpobrotus.
EOO 128 sq km
AOO 12 sq km
Only known from 3 (formerly 4) mid-elevation locations on Saint Helena
Population and Trends
Only known from 3 locations, each consisting of dozens individual thalli, but covering in total not more than one square meter.
One previously known locality disappeared with the building of the airport.
There may be some additional, not yet discovered, localities.
Population Trend: Decreasing
Habitat and Ecology
On gravelly soil in upland desert areas.
With the increasing tourism on Saint Helena as a result of the new airport, this terrestrial lichen risks to get trampled.
Also, its habitat is rapidly diminishing because of the rapid spread of the invasive plant Carpobrotus.
Recreational activitiesNamed species
The remaining localities should be protected from trampling, e.g. by a fence, and the invasive Carpobrotus should be eradicated from these locations.
It is possible, but not very probable, that some yet undiscoverd localities exist, elseweher on Saint Helena. They could be looked for by speciaists.