Straminergon Hedenäs

Straminergon is a monotypic genus erected by Hedenäs (1993) to accommodate the widespread but predominantly northern hemisphere S. stramineum. Compared to other genera in what he termed the "Calliergon-Scorpidium-Drepanocladus complex", S. stramineum is distinguished by yellow-brown colouration, well-developed alar groups, and strongly and irregularly dentate upper margins of the perichaetial leaves. He also emphasised the sparse branching of the shoots, ovate stem leaves with an obtuse apex, and relatively short and sparse axillary hairs as features characteristic of the genus.

Straminergon stramineum has been traditionally treated in the genus Calliergon (Brotherus 1925). It may be conveniently distinguished from the one species of Calliergon s.s. occurring in N.Z. by its more slender and more sparsely branched stems, smaller stem leaves which are imbricate and striolate (especially when dry), and lack of differentiated branch leaves. The species description below applies to the genus.