Riccardia sphagnicola sp. nov. (Marchantiophyta, Aneuraceae) a filamentous penalpine bog species of the New Zealand mountains with a comparison to six similar New Zealand species

Abstract

Riccardia sphagnicola is described from seven penalpine locations and one coastal location in both North and South islands, New Zealand. It is similar to six filamentous Riccardia species in New Zealand that have a main axis less than 0.6 mm wide (R. breviala, R. lobulata, R. papulosa, R. aequicellularis, R. multicorpora, and R. asperulata), five of which also have an unornamented epidermis. In all seven species, epidermal cells are approximately equal in size to internal thallus cells, a marginal wing no more than one unistratose cell wide, and endomycorrhizae absent or difficult to see. Riccardia sphagnicola is more robust than the others, as measured by main axis width and depth. It is most similar to R. breviala but differs in a number of respects, including habitat differences. Riccardia sphagnicola is brown in older parts of thallus versus uniformly yellow-green in R. breviala; it is loosely prostrate versus prostrate with erect branches; it has branch apices rounded versus slightly retuse; mucilage papillae at shoot apices are always present versus usually absent. Stolons in Riccardia sphagnicola are rare but common in R. breviala. Riccardia sphagnicola is mainly known from bogs in the penalpine zone whereas R. breviala is a forest species on a mineral soil substrate and does not reach the penalpine zone. Riccardia asperulata is reported new for Tasmania and Australia as a result of this study.