Myosotis brevis

Myosotis brevis plants are single rosettes. The rosette leaves have petioles 1–7 mm long. The rosette leaf blades are 1–9 mm long by 1–4 mm wide (length: width ratio 1.2–2.5: 1), narrowly oblanceolate to broadly obovate, widest at or above the middle, green or brown, with an obtuse (occasionally acute) apex. The upper surface of the leaf is densely covered in flexuous, appressed to erect, antrorse (forward-facing) hairs, whereas the lower surface of the leaf is similar but with fewer hairs (ranging from glabrous to with sparsely distributed hairs). Each rosette has multiple prostrate, bracteate inflorescences that are up to 5 cm long. The cauline leaves are similar in size and shape to the rosette leaves and become sessile toward the tip. Each inflorescence has up to 17 flowers, each borne on a very short pedicel, with a bract.

The calyx is 1–2 mm long at flowering and 2–4 mm long at fruiting, lobed to one-third or two-thirds its length, and hairs that are more densely distributed on the calyx ribs, and sometimes of two different lengths and types. The corolla is white or cream, or sometimes pale blue or blue-striped, up to 2 mm in diameter, with a cylindrical tube, and small yellow scales alternating with the petals. The anthers are very short (usually < 0.3 mm long) and fully included. The four smooth, shiny nutlets are usually 0.9–1.2 mm long by 0.5–0.8 mm wide and are ovoid in shape.[3] M. brevis has M. discolor type pollen, which is distinctive amongst all bracteate-prostrate species in New Zealand.[4][5] It flowers during the months September–April and fruits during the months October–April. Peak flowering and fruiting occurs October–December.[3]

Myosotis brevis de Lange & Barkla is in the plant family Boraginaceae, was originally described as M. pygmaea var. minutiflora in 1942 by George Simpson and J.S. Thomson, and was later recognized at species rank by Peter de Lange and John Barkla, as M. brevis, in 2010.[6][7][8][9] The species required a new name since M. minutiflora Boiss. & Reut., an unrelated northern hemisphere species, was already published.[10][11] The most recent taxonomic revision continues to recognize M. brevis at the species level, and it ss morphologically most similar to the other bracteate-prostrate species endemic to New Zealand in the pygmy subgroup, i.e. Myosotis glauca and M. antarctica.[3] Myosotis brevis is the smallest New Zealand forget-me-not and differs from all other Myosotis in its small corolla (<2.0 mm diameter), short calyx (<1.7 mm at flowering), and small nutlets [0.9–1.2(–1.4) mm long by 0.5–0.8 mm wide].[3][12]

The holotype specimen of Myosotis pygmaea var. minutiflora is lodged at the Allan Herbarium (CHR) of Manaaki Whenua - Landcare Research (CHR 75725).[13] The specific epithet, brevis, is derived from Latin and means 'short', whereas minutiflora is also derived from Latin and means 'small flowered'.

Myosotis brevis is a forget-me-not endemic to coastal areas in the North Island (Taranaki, Southern North Island) and mountainous areas of Canterbury and Otago of the South Island of New Zealand, from 0–1900 m ASL. M. brevis is found in herb fields, turfs and gravels of coastal cliffs, platforms and beaches on the North Island; at the edges of seasonally inundated tarn edges in Canterbury; and in exposed, dry to seasonally moist alpine fellfield, pasture or turf in Otago.[3]

The species is listed as "Threatened - Nationally Vulnerable" on the most recent assessment (2017-2018) under the New Zealand Threatened Classification system for plants, with the qualifiers "EF" (Extreme Fluctuations) and "Sp" (Sparse).[1] A recent taxonomic revision recommended maintaining this conservation status and qualifiers.[3]

• Myosotis brevis occurrence data from Australasian Virtual Herbarium
• Media related to Myosotis brevis at Wikimedia Commons