''Myosotis colensoi'' is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Boraginaceae Boraginaceae, the borage or forget-me-not family, includes about 2,000 species of shrubs, trees and herbs in 146, to 156 genera with a worldwide distribution. The APG IV system from 2016 classifies the Boraginaceae as single family of the order ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

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 ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. Thomas Kirk described the species in 1896. Plants of this species of

forget-me-not ''Myosotis'' ( ) is a genus of flowering plants in the family Boraginaceae. The name comes from the Ancient Greek "mouse's ear", which the foliage is thought to resemble. In the northern hemisphere they are colloquially known as forget-me-nots ...

are

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

rosettes with bracteate inflorescences and white corollas.

Taxonomy and etymology

''Myosotis colensoi'' (

Kirk Kirk is a Scottish and former Northern English word meaning "church". It is often used specifically of the Church of Scotland. Many place names and personal names are also derived from it. Basic meaning and etymology As a common noun, ''kirk'' ...

) J.F.Macbr. is in the plant family

and was originally described (as ''Exarrhena colensoi'' Kirk) in 1896 by Thomas Kirk. ''M colensoi'' is morphologically most similar to '' M. cheesemanii,'' from which it can be distinguished by its rosette laminas which are longer (> 6.8 mm) with a larger length : width ratio (2.2–3.1 : 1), shorter petioles, and larger rosettes. The type specimen of ''Myosotis colensoi'' is lodged at the

Museum of New Zealand Te Papa Tongarewa The Museum of New Zealand Te Papa Tongarewa is New Zealand's national museum and is located in Wellington. ''Te Papa Tongarewa'' translates literally to "container of treasures" or in full "container of treasured things and people that spring fr ...

, Wellington (herbarium WELT). The specific epithet, ''colensoi'', is named after New Zealand missionary and botanist,

William Colenso William Colenso (17 November 1811 – 10 February 1899) FRS was a Cornish Christian missionary to New Zealand, and also a printer, botanist, explorer and politician. He attended the signing of the Treaty of Waitangi and later wrote an accou ...

1811–1899).

Phylogeny

''Myosotis colensoi'' was shown to be a part of the

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

southern hemisphere lineage of ''Myosotis'' in

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analyses of standard DNA sequencing markers ( nuclear ribosomal DNA and

chloroplast DNA Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nu ...

regions). Within the southern hemisphere lineage, species relationships were not well resolved.

Description

''Myosotis colensoi'' plants are single rosettes that grow close together forming loose clumps. The rosette leaves have petioles 2–16 mm long. The rosette leaf blades are 4–15 mm long by 0.6–2 mm wide (length: width ratio 2.2–3.8: 1), oblanceolate to narrowly obovate or rarely narrowly elliptic to elliptic, widest at or above the middle, with an obtuse and often retuse 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 but often only a few isolated hairs are present. Each rosette has 3–13 prostrate, unbranched, bracteate

inflorescences An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

that are (14)32–76 mm long. The cauline leaves on the lower part of the inflorescence are similar to but smaller than the rosette leaves, but usually sparsely to densely hairy on the lower surface, and decrease in size and become sessile toward the tip. There can be up to 12 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 3–7 mm long at flowering and 4–8 mm long at fruiting, lobed to about a third of its length, and densely covered in short, straight, appressed to patent, antrorse hairs. The corolla is white up to 9 mm in diameter, with a cylindrical tube, petals that are obovate to very broadly 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 1.3–1.8 mm long by 0.8–1.1 mm wide and ovoid (rarely narrowly ovoid) in shape. ''Myosotis colensoi'' has ''M. australis'' type pollen. The chromosome number of ''M. colensoi'' is 2''n'' = 46 (CHR100916). The breeding system of ''Myosotis colensoi'' is

outcrossing Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful ...

, as the flowers are 'always herkogamous', with a high pollen : ovule ratio, and no seed production in enclosed flowers. Nevertheless, the species is also fully

self-compatible Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...

. ''Myosotis colensoi'' flowers and fruits from (September–)November–January(–April).

Distribution and habitat

''Myosotis colensoi'' is endemic to the South Island of New Zealand in Marlborough (Chalk Range) and Canterbury (Castle Hill area), from 610–1050 m ASL. ''M. colensoi'' is found on dry, exposed limestone. In Canterbury, it may be found with the Castle Hill buttercup, '' Ranunculus paucifolius.'' It is considered to be an obligate

calcicole A calcicole, calciphyte or calciphile is a plant that thrives in lime rich soil. The word is derived from the Latin 'to dwell on chalk'. Under acidic conditions, aluminium becomes more soluble and phosphate less. As a consequence, calcicoles grown ...

Conservation status

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

References

External links

''Myosotis colensoi'' occurrence data from Australasian Virtual Herbarium
* {{Taxonbar, from=Q17416576 colensoi Endemic flora of New Zealand Endangered flora of New Zealand Plants described in 1896 Taxa named by Thomas Kirk