''Myosotis cheesemanii'' is a species of flowering plant in the family Boraginaceae, endemic to the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

of New Zealand. Donald Petrie described the species in 1886. Plants of this species of forget-me-not are perennial rosettes with bracteate inflorescences and white corollas.

Taxonomy and etymology

''Myosotis cheesemanii'' Petrie is in the plant family Boraginaceae and was originally described in 1886 by Donald Petrie. ''M cheesemanii'' is morphologically most similar to '' M. colensoi,'' from which it can be distinguished by its rosette laminas which are shorter (< 6.4 mm) with a smaller length : width ratio (1.2–1.9 : 1), longer petioles, and smaller rosettes. The type specimen of ''Myosotis cheesemanii'' is lodged at the Museum of New Zealand Te Papa Tongarewa, Wellington (herbarium WELT). Anthony Druce collected the type specimen of this species from Takaka Valley in north-west Nelson in 1977. The specific epithet, ''cheesemanii'', is named after New Zealand botanist

Thomas Cheeseman Thomas Frederick Cheeseman (8 June 184515 October 1923) was a New Zealand botanist. He was also a naturalist who had wide-ranging interests, such that he even described a few species of sea slugs (marine gastropod molluscs). Biography Chees ...

(1845–1923).

Phylogeny

''Myosotis cheesemanii'' was not included in phylogenetic analyses of standard DNA sequencing markers (

nuclear ribosomal DNA Nuclear may refer to: Physics Relating to the Atomic nucleus, nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear ...

and chloroplast DNA regions).

Description

''Myosotis cheesemanii'' plants are single rosettes that grow close together forming loose clumps. The rosette leaves have petioles 1–6 mm long. The rosette leaf blades are 3–9 mm long by 1–3 mm wide (length: width ratio 1.2–2.2: 1), narrowly obovate or broadly obovate, rarely elliptic or broadly ovate, widest at or above the middle, with an obtuse apex. The upper surface of the leaf is densely covered in straight, mostly appressed, antrorse (forward-facing) hairs that are parallel to the mid vein, while on the lower surface the hairs are the same or sometimes the hairs are fewer or even lacking. Each rosette has 4–7 prostrate, sometimes ascending, unbranched, bracteate inflorescences that are 14–36 mm long. The cauline leaves on the lower part of the inflorescence are similar to but smaller than the rosette leaves, but usually with an acute apex, and decrease in size toward the tip. There can be up to 5 flowers in each inflorescence, each one borne on a short

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

and with a bract. The calyx is 4–5 mm long at flowering and 5–6 mm long at fruiting, lobed to about a third of its length, and densely covered in short, straight, appressed, antrorse hairs. The corolla is white up to 8 mm in diameter, with a cylindrical tube, petals that are broadly obovate and flat, and small yellow scales alternating with the petals. The anthers are partially exserted, with the tips only surpassing the scales. The four smooth, shiny, medium brown nutlets are about 1.7 mm long by about 0.9 mm wide and ovoid or narrowly ovoid in shape. ''Myosotis cheesemanii'' has ''M. uniflora'' type pollen. The chromosome number of ''M. cheesemanii'' is unknown. It flowers in January and fruits in February.

Distribution and habitat

''Myosotis cheesemanii'' is endemic to the South Island of New Zealand in Otago, from (780–)1700–1800 m ASL m elevation. ''M. cheesemanii'' is found in herbfields, on steep shingle faces, at the base of schist tors, or near snowdrifts.

Conservation status

The species is listed as Threatened - Nationally Critical the most recent assessment (2017-2018) of the New Zealand Threatened Classification for plants. It also has the qualifiers "DP" (Data Poor), "RR" (Sparse) and "Sp" (Sparse).

References

External links

''Myosotis cheesemanii'' occurrence data from Australasian Virtual Herbarium
* {{Taxonbar, from=Q21397832 cheesemanii Endemic flora of New Zealand Endangered flora of New Zealand Plants described in 1886 Taxa named by Donald Petrie