Myosotidium hortensia
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Myosotidium hortensia |
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| Scientific name of the genus | ||||||||||||
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| ( Decne. ) Baill. |
Myosotidium hortensia is the only kind of monotypic genus Myosotidium within the family of Borage Family (Boraginaceae).
description
Vegetative characteristics
Myosotidium hortensia is a perennial herbaceous plant that can reach a height of up to 1 meter. It grows into larger clumps with a diameter of up to 1 to 1.5 meters. The compact, cylindrical and somewhat fleshy rhizome has numerous leaf scars on the surface.
The leaves become coarser with age. The leaves are divided into a petiole and a leaf blade. The petioles are 10 to 50 centimeters long, grooved on the top and fluted on the underside. The thick and fleshy to leathery, dark-green to yellow-greenish leaf blades are up to 40 centimeters wide and roughly heart-shaped or kidney-shaped, with a shiny surface. The underside of the leaf is lighter and evenly hairy. The leaf margins are whole and the leaf veins protrude on the underside.
Generative characteristics
The flowering time on the Chatham Islands extends from September to November. The inflorescences are umbrella-shaped cymes with a woody base and small stem leaves. The inflorescences are 10 to 20 centimeters in diameter. The flower stalks are 10 to 15 millimeters long.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five hairy sepals are 2.0 to 2.5 millimeters long and 1.8 to 4.5 millimeters wide and elliptical with a blunt upper end and entire margins. The corolla is 12 to 15 millimeters in diameter, dark to light blue, often discolored purple over time and occasionally white. The petals are blue and purple or purple in color. The five overlapping petals are 4.0 to 4.5 millimeters × 5.0 to 6.0 millimeters, round and flat. The corolla tube is 2 millimeters long, the "throat" partially covered by five fleshy outgrowths. The stamens are 0.5 millimeters long, fused near the "throat" with the 1.0 to 1.2 millimeter long anthers. The ovary is four-lobed, 0.7 to 1.0 millimeters long with an upper scar.
The nuts are 10 to 15 millimeters in diameter, brown to black and winged. The seed is egg-shaped with a length of 7.5 to 9.0 millimeters.
The number of chromosomes is 2n = 40 to 42.
There is also a white flowered cultivar 'Alba'.
Occurrence
Myosotidium hortensia is endemic and only occurs on the chatham islands. There are localities on Chatham (Rekohu), Pitt, South East, Mangere and most of the small to tiny islands and on some rocks in the sea.
Systematics
It was first described in 1846 by Joseph Decaisne as Myosotis hortensia . In 1859, William Jackson Hooker established the genus Myosotidium and described a species with Myosotidium nobile that is now considered a synonym . Finally, in 1890, Henri Ernest Baillon placed the first described species Myosotis hortensia as Myosotidium hortensia in the genus.
The origin of this species is uncertain, but it is believed that the ancestors came from the American continent. The closest relatives are probably the species of the genus Selkirkia in South America, as well as the North American genus Mimophytum .
Individual evidence
- ↑ Myosotidium hortensia on the New Zealand Plant Conservation Network (accessed January 31, 2017)
- ↑ Icones selectae plantarum Volume 5, p. 42, Ill. Plate 92, Paris 1846 scanned .
- ↑ Curtis's Botanical Magazine , Volume 85, 5137. London 1859 board scanned .
- ↑ Histoire des plantes , Volume 10, p. 383, Paris scanned in 1890 .
- ↑ N. Holstein, J. Chacón, HH Hilger, M. Weigend: No longer shipwrecked - Selkirkia (Boraginaceae) back on the mainland with generic rearrangements in South American “ Omphalodes ” based on molecular data . In: Phytotaxa . 270, No. 4, 2016, pp. 231-251. doi : 10.11646 / phytotaxa.270.4.1 .
- ↑ N. Holstein, J. Chacón, A. Otero, P. Jiménez-Mejías, M. Weigend: Towards a monophyletic Omphalodes —or an expansion of North American Mimophytum . In: Phytotaxa . 288, No. 2, 2016, pp. 131–144. doi : 10.11646 / phytotaxa.288.2.3 .
