Siphula flavovirens
Siphula flavovirens is a species of terricolous fruticose lichen in the family Icmadophilaceae. It occurs in the Succulent Karoo biome of South Africa.
Taxonomy
Siphula flavovirens was described as a new species by the lichenologists Gintaras Kantvilas, Luciana Zedda, and John Elix in 2003, based on specimens collected from Namaqualand in the Northern Cape Province of South Africa. The type specimen was collected by Zedda near Soebatsfontein in the Succulent Karoo biome, at an elevation of. It is deposited at PRE, the herbarium of the South African National Biodiversity Institute in Pretoria. The species epithet flavovirens alludes to its distinctive yellowish-green colouration, which resembles lichens in the genus Xanthoparmelia; this yellowish colouration is rare in the genus Siphula.Description
Siphula flavovirens is a small, fruticose lichen that typically forms dense tufts or mats about 5–9 mm tall, occasionally reaching up to 10 mm. The species is characterized by broadly flattened, fragile that stand erect or ascending, often densely crowded and intertwined, and sometimes perforated with holes. Its lobes range from 0.5 to 3 mm wide and have identical dorsal and ventral surfaces. The surface texture is notably rough,, mealy, and irregularly puckered, with colours ranging from dull yellow-green to pale beige-brown, particularly near the base. The lobes lack a developed and instead have an outer layer composed of loose, short-celled hyphae extending from the medulla.Chemically, Siphula flavovirens is unique among its genus due to the presence of usnic acid and caloploicin, the latter being recorded for the first time in the genus Siphula with the publication of this species. This chemical composition distinguishes it significantly from other closely related species, particularly those within the 'Siphula decumbens group' which predominantly contain depsides such as thamnolic and hypothamnolic acids.