Siderasis is a genus of monocotyledonous flowering plants belonging to the family Commelinaceae (the dayflower family), first described in 1837. It is native to the State of Rio de Janeiro in southeastern Brazil and is widely treated as monotypic, with Siderasis fuscata as its sole recognised species, though the genus is also naturalized on the island of Java in Indonesia.
Plants in this genus are noted for their striking foliage: the leaves are broad and oval, densely covered in fine hairs, with green upper surfaces that carry silvery and reddish hues and a pale stripe running down the centre. The undersides of the leaves are reddish purple, giving the plant an ornamental two-toned appearance. These hairy, ear-shaped leaves account for the common English name "bear's ears," while the brownish-chocolate tones of the foliage give rise to the alternative name "brown spiderwort."
The flowers bear three bluish-purple petals and closely resemble those of Tradescantia, the genus to which Siderasis was formerly assigned within the tribe Tradescantiae. It is now treated as a distinct genus within the family Commelinaceae, order Commelinales. In warmer climates Siderasis can be cultivated in parks and gardens; in temperate regions it is grown in botanical garden glasshouses and kept as a houseplant.
Distribution
Siderasis is endemic to the State of Rio de Janeiro in southeastern Brazil. It has also become naturalized on the island of Java in Indonesia, likely through horticultural introduction.
Ecology
In warmer climates, Siderasis is planted in parks and gardens. In temperate regions it is maintained in botanical garden glasshouses and commonly grown as a houseplant, valued for its ornamental foliage.
Cultivation
Siderasis fuscata is cultivated as a houseplant in temperate regions and as a garden plant in warmer climates. It is suited to shaded conditions and is appreciated for its striking two-toned leaves with fine, dense hairs.
Taxonomy Notes
Siderasis was first described in 1837. It was formerly placed within the tribe Tradescantiae due to the close resemblance of its flowers to those of Tradescantia, but is now recognised as a distinct genus in the family Commelinaceae, order Commelinales. GBIF treats the genus as monotypic (one accepted descendant taxon under key 103027654), consistent with the Wikipedia account.
