About Myosotis uniflora Hook.fil.
Myosotis uniflora Hook.fil. plants grow as compact cushions or mats that can reach 50 cm in diameter. This species has numerous overlapping imbricate rosette leaves, with petioles 1–4 mm long that are hairless except for erect hairs along their edges. Rosette leaf blades measure 1–4 mm long by approximately 1 mm wide, giving a length to width ratio of 1.4–4.1:1. Leaf blades are lanceolate to ovate or triangular, widest at or below the middle, and have an acute apex. Both upper and lower leaf surfaces are sparsely to densely covered in long, flexuous, forward-facing (antrorse) hairs that lie either appressed against or spreading out from the leaf, and are oriented parallel to the mid vein.
Each rosette produces a small number of prostrate to ascending, once-branched, bracteate inflorescences that grow up to 60 mm long. Cauline leaves are similar in shape to rosette leaves but smaller in size. Each inflorescence holds just one solitary flower, which is borne on a short pedicel and accompanied by a bract. The calyx is 1–4 mm long when flowering, growing to 2–5 mm long during fruiting, and is lobed to approximately half of its total length. It is densely covered in long, flexuous, antrorse hairs that are mostly appressed with a small number spreading; these hairs are rarely hooked at the base of the calyx.
The corolla ranges from cream to yellow, and is 2–7 mm in diameter. It has a cylindrical tube, flat petals that are obovate to very broadly obovate or ovate to very broadly ovate, and small yellow scales that alternate with the petals. The anthers are usually fully included within the corolla, though sometimes they are only partially included, with just the anther tips extending past the scales. The four smooth, shiny, dark brown nutlets are 1.4–1.7 mm long by 0.8–1.4 mm wide, and range from narrowly to broadly ovoid in shape. Myosotis uniflora has pollen of the M. uniflora type.
The breeding system of this species is outcrossing: its flowers are always herkogamous, and it has a high pollen to ovule ratio. It flowers and fruits between September and March, with the main flowering period from October to January and the main fruiting period from November to March.
Myosotis uniflora is a forget-me-not endemic to the South Island of New Zealand. It occurs in the ecological districts of Canterbury and Otago at 210–850 m above sea level; it is mainly found in Otago, but is also recorded from Westland, Canterbury, and Fiordland at 1020–2130 m ASL. Plants grow scattered across lowland river-bed flats and terraces alongside other cushion plants, herbs, and subshrubs. They are closely associated with cushionfield, moss-stonefield, and stonefield plant communities in upper river catchments.
