Struthiola is a genus of around 40 ericoid shrubs and shrublets in the family Thymelaeaceae, order Malvales. The genus is almost entirely African in distribution, with its greatest diversity centred in the Western Cape of South Africa, where about 25 species are endemic to the fynbos biome; the range extends northward to Ethiopia.
Plants in the genus are typically small, wiry shrubs with leaves that are usually opposite (occasionally alternate). The flowers are sessile and generally solitary in the axils of the upper leaves, each subtended by a pair of ciliate bracteoles. The calyx forms a roughly cylindrical tube ending in four ovate to linear lobes. Four to twelve fleshy, subterete petal-scales sit within the calyx, shorter than the lobes and fringed with short hairs. Four stamens arise deep within the calyx tube; the anthers are subsessile and linear. The small dry fruit, typically 1–3 mm, is enclosed within the persistent base of the calyx tube — a structure that has been compared to a sparrow's beak, and from which the genus takes its name.
Despite their modest, ericoid appearance, several species are prized by plant collectors for their unexpectedly arresting nocturnal scent, produced to attract the small, fine-proboscid moths that pollinate them. Struthiola myrsinites and Struthiola ciliata are among the species cultivated in gardens, particularly in South Africa.
Etymology
The name Struthiola derives from the Latin strutheus (sparrow) or Greek strouthos (any small bird), alluding to the shape of the fruit enclosed in the remnant calyx tube, which was thought to resemble a bird's beak. Common names in South African vernacular include "gonna", "soetgonna", and "aandgonna" (evening gonna), though these names are also loosely applied to the related genus Passerina and other Thymelaeaceae.
Distribution
Struthiola ranges across sub-Saharan Africa from Ethiopia south to the Cape, with the overwhelming majority of species concentrated in the Western Cape of South Africa. Approximately 25 species are endemic to the fynbos shrubland biome of the Cape Floristic Region.
Ecology
Species of Struthiola are characteristic components of fynbos scrub. Their narrow, tubular flowers and strong nocturnal fragrance are adapted for pollination by small moths with fine proboscises, making them functional night-bloomers despite being inconspicuous by day.
Cultivation
Struthiola species are cultivated primarily by collectors of fynbos plants. They are valued for their delicate, unexpectedly strong nocturnal scent — a single plant can fragrance a porch on a still warm night. Struthiola myrsinites is noted for its relatively showy flowers. Their modest ericoid habit means flowering can be easily overlooked in daytime, but the plants are considered rewarding for enthusiasts.
