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The giant tree-groundsels in the genus Dendrosenecio are tree-like plants in the daisy family (Asteraceae), a group of predominantly herbaceous plants. Their closest relatives are African representatives of a group that includes the temperate ragworts and groundsels in the genus Senecio (Knox & Palmer 1995). The 11 species of Dendrosenecio inhabit the high-altitude alpine tundras of the East African Rift Valley system, including Mt. Kilimanjaro, Mt. Kenya, Mt. Rwenzori, Mt. Elgon, and the Virunga Mountains (Knox 1993). These mountain ranges represent isolated sky islands surrounded by tropical forests and savannas, and each has its own endemic group of Dendrosenecio species (Moore 2008, Cox & Moore 2010).
Dendrosenecio species are adapted to a harsh environment where the equatorial sun bears down during the day and temperatures often drop below freezing at night (Hedberg 1964). In some species, the trunk is insulated by a thick layer of leaves that remain on the plant long after they have died (marcescence). Also, fresh leaves contain a thick slime with anti-freeze qualities, and at the onset of darkness they can close around growing buds (nyctinasty) to protect them from freezing (Calow 1998).