Cylindrocline is a small genus of flowering plants in the daisy family Asteraceae (order Asterales), described by the French botanist Alexandre Henri Gabriel de Cassini (author abbreviation "Cass."). The genus is remarkable for its extreme rarity: it comprises only two species, both endemic to the island of Mauritius in the south-western Indian Ocean, making it one of the most geographically restricted genera in the entire daisy family.
The two species — Cylindrocline commersonii Cass. and Cylindrocline lorencei A.J.Scott — are subshrubs or shrubs associated with the montane tropical forests and heathlands of Mauritius, particularly the upland plateau of Plaine Champagne. Like much of the Mascarene island flora, both species have been severely affected by habitat destruction, invasive species, and the long history of land-use change on Mauritius following European colonisation. Cylindrocline lorencei has been recorded as extinct in the wild in Mauritius, and survives only through ex-situ conservation efforts at institutions including the Botanical Conservatory of Brest in France. Cylindrocline commersonii is likewise considered critically threatened. Their plight has been documented in conservation literature including Curtis's Botanical Magazine ("Plants in Peril" series) and in the global plant extinction dataset of Humphreys et al. (2019, Nature Ecology & Evolution).
The genus stands as a symbol of the broader conservation crisis facing the flora of the Mascarene Islands, where high endemism combined with small island area and intensive anthropogenic pressure has driven many plant lineages to the brink of extinction.
Etymology
The genus name Cylindrocline was coined by the French botanist Alexandre Henri Gabriel de Cassini (Cass.), who described the genus in the early nineteenth century. The name derives from Greek roots: kylindros (cylinder) and klinē (bed or receptacle), likely referring to the form of the receptacle or floret arrangement in the flower head. The author abbreviation "Cass." is standard for Cassini in botanical nomenclature.
Distribution
Cylindrocline is endemic to the island of Mauritius in the Indian Ocean, with both species restricted to a small area of the montane plateau known as Plaine Champagne. This highly localised distribution makes the genus one of the most range-restricted in Asteraceae. No wild populations are known outside Mauritius; ex-situ plants are maintained at botanical gardens in Europe, notably the Botanical Conservatory of Brest in France.
Conservation
Both species of Cylindrocline face extreme conservation concern. Cylindrocline lorencei is considered extinct in the wild in Mauritius, persisting only in ex-situ cultivation; it was featured in Curtis's Botanical Magazine "Plants in Peril" series (issue 31) and is included in the Humphreys et al. (2019, Nature Ecology & Evolution) global dataset of modern plant extinctions. Conservation repatriation work was documented by Sarasan (2006) and Mascarene flora conservation by Strahm (1996). The genus exemplifies the severe threat to island-endemic plant genera from habitat loss and invasive species.
