Myosotis umbrosa is a species of flowering plant in the family Boraginaceae, endemic to the South Island of New Zealand. Heidi Meudt, Jessica Prebble and Michael Thorsen described the species. Plants of this species of forget-me-not are perennial with a prostrate habit, bracteate inflorescences, and white corollas.
Myosotis umbrosa Meudt et al. is in the plant family Boraginaceae and was originally described in 2018 by Heid Meudt, Jessica Prebble and Michael Thorsen.[2][3] It is morphologically most similar to M. antarctica and M. lyallii, but can be distinguished from them and other bracteate-prostrate species of Myosotis by a combination of retrorse (backward facing) hairs on the underside of the leaf, hooked hairs and retrorse hairs on the base of the calyx, and flowers sometimes slightly below cauline leaf axils.[2]
Myosotis umbrosa plants are single rosettes. The rosette leaves are 4–14 per plant, and have petioles 6–25mm long. The rosette leaf blades are 6–31mm long by 4–10mm wide (length: width ratio 1.7–3.2: 1), widest at or above the middle, usually oblanceolate to narrowly obovate, with an obtuse apex. The upper surface of the leaf is sparsely to densely covered in flexuous, patent to erect, antrorse (forward-facing) hairs that are oriented at an angle relative to the mid vein. The lower surface of the leaf is sparsely to densely covered in flexuous, patent to erect, retrorse (backward-facing) hairs, that are also angled relative to the mid vein. Each rosette has 2–7 prostrate, unbranched, bracteate inflorescences that are 11–110mm long. The cauline leaves are similar in size, shape and hairs to the rosette leaves, but smaller and becoming sessile toward the tips of the inflorescences. There can be up to 13 flowers in each inflorescence, each one borne on a short pedicel and with a cauline leaf. The calyx is 2–3mm long at flowering and 3–5mm long at fruiting, lobed to about half of its length, and densely covered in long, flexuous, patent to erect antrorse hairs, with some hooked hairs and some retrorse hairs near the calyx base. The corolla is white and up to 5mm in diameter, with a cylindrical tube, petals that are broadly to very broadly obovate and flat, and small yellow scales alternating with the petals. The anthers are fully included, or rarely partially exserted with the tips just reaching or surpassing the scales. The four smooth, shiny, light to dark brown nutlets are 1.6–1.7mm long by 1.2–1.3mm wide and ovoid to broadly ovoid in shape.[2][7]
Myosotis umbrosa has M. australis type pollen with 8, 10 or 12 apertures.[8][9]
The chromosome number of M. umbrosa is unknown.
It flowers and fruits mainly from December to February.[2]
Pollen
Habit
Flowers
Close up of upper and lower rosette leaf surface
Close up of lower rosette leaf surface and tip of flowering branch
Distribution and habitat
Myosotis umbrosa is endemic to the South Island of New Zealand in Otago, known only from the Rock and Pillar and Lammerlaw Ranges, from 915–1370m elevation.[2] It is found in shady, rocky areas often at the base of tors.[2]
Flowering plant at the base of a rock tor in the Rock and Pillar Range
Flowering individual amongst grasses and moss in its natural habitat
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 "DP" (Data Poor), "RR" (Range Restricted), and "Sp" (Sparse).[1]
References
12Lange, Peter J. de; Rolfe, Jeremy R.; Barkla, John W.; Courtney, Shannel P.; Champion, Paul D.; Perrie, Leon R.; Beadel, Sarah M.; Ford, Kerry A.; Breitwieser, Ilse; Schönberger, Ines; Hindmarsh-Walls, Rowan (May 2018). "Conservation status of New Zealand indigenous vascular plants, 2017"(PDF). New Zealand Threat Classification Series. 22: 1–86. OCLC1041649797.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
