English: Marsh rose.
Name: in Greek oros means mountain, thamnos means bush.
Genus: 1 species.
Region: Kogelberg and Kleinrivier Mountains, Western Cape Province, South Africa.
Habitat: fynbos; peaty swamps and seeps; altitudes of 450 to 850 m.
Ecology: extremely rare and endangered; fungus Phytophthora causes death
BotanyErect, sparsely branched shrub; 5 m tall; short-lived, 10 to 20 years; readily killed by fire
Seeds: long-lived; viable for over 35 years below ground; need summer fires to germinate.