Mellissia begoniifolia
| Mellissia begoniifolia | ||||||||||||
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Mellissia begoniifolia |
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| Mellissia begoniifolia | ||||||||||||
| ( Roxb. ) Hook.f. |
Mellissia begoniifolia (often, but incorrectly, also Mellissia begonifolia ) is a species ofthe nightshade family (Solanaceae). It is the only species in the genus Mellissia . It grows endemic to St. Helena , where it was long thought to be extinct but was rediscovered in 1998.
description
Vegetative characteristics
Mellissia begoniifolia are up to 2.5 m high, expansive and open-growing shrubs , which in their natural location are seasonally deciduous, but which grow evergreen in culture. The thin branches are noticeably stunted; flower-bearing branches are often shaped like a zigzag. The bark of the trunk and the older branches is dark reddish-brown, with longitudinal green stripes.
The leaves are in alternate pairs in a 3/5 phyllotaxis . They stand in dense groups at the tips of the branches, especially on branches that carry flowers. The leaf blade is somewhat fleshy, narrowly elliptical to ovate and has a length of 1.5 to 4.5 cm and a width of 1 to 3 cm, the petioles are 1 to 3 cm long. On branches that do not have flowers, the leaves are usually slightly larger and are up to 6 cm long and 4 cm wide, the petioles then reach a length between 2.8 and 8 cm. Towards the front, the leaf blade is cut off-rounded to pointed, the base is heart-shaped or cut off, the leaf margin is entire. The leaves are evenly hairy with simple, single-row, glandular and only about 0.01 mm long trichomes , which makes the leaves slightly sticky to the touch. The smell of the leaves is described as similar to tobacco or similar to the smell of the leaves of the bladder cherries ( Physalis ); the comparison with the smell of sweaty feet was also used.
blossoms
The flowers stand individually between the leaves of a pair of leaves. The flower stalks are 0.8 to 1.2 cm long, the flowers themselves are nodding or drooping. The elliptical buds are up to 2.5 cm in diameter. During the flowering period, the calyx , which consists of overgrown sepals , is green, open bowl-shaped and irregularly shaped and not covered with trichomes. The calyx tube has a length of 0.6 to 1.3 cm, the calyx lobes are 0.2 to 1 cm long and form an irregularly wavy edge. The petals are fused bell-shaped, the crown measures about 1.5 cm in diameter. It has five pairs of irregular, green spots that are located in the throat on the lines of adhesion of the petals. The corolla tube has a length of 0.6 to 0.8 cm, in it there are conspicuous nectar droplets between the green spots, about 0.3 to 0.5 cm from the base. Each petal has a depression in the lower half along the central vein, which is finely hairy. The corolla lobes are 0.4 to 0.5 cm long, the tip is rounded, while the corolla lobes bend back during flowering.
The five stamens elongate to maturity, so that the stamens are then 0.35 to 0.4 mm long. The anthers are elliptical in shape and have a length of about 0.15 mm, they open like a slit. The pollen is creamy yellow. The ovary is conical and hairless. The stylus is just colored, white and has a length of 0.4 to 0.5 cm, the scar is zweigelappt something and also white.
Fruits and seeds
The fruits are slightly conical berries with a diameter of up to 0.6 cm , which are initially green and when ripe they dry up and turn brown; the pericarp is thin and papery. When ripe, the calyx and fruit fall off the plant together, the calyx is then yellow and also dries up.
Each fruit contains around ten to 15 seeds . These are black, elliptical-kidney-shaped and about 1.0 × 0.5 mm in size. The seed surface is finely grained.
Occurrence, locations and endangerment
The species is endemic to the island of St. Helena , in the southeast of which it grows on stony slopes. It is the only species of the nightshade family that is part of the island's natural flora. However, a number of other species in the family have been introduced by humans, some of which are dangerous invasive species . Mellissia begoniifolia had been considered extinct since at least the end of the 19th century , until in 1998 a hiker accidentally found one living and six dead plants at an altitude of 100 m on a slope facing the sea. The living plant was heavily insect- infested, but was in bloom and producing fruit. Cuttings that were taken from the plant did not keep in culture, but over 400 seeds could be collected, which were grown on the island, but also in various botanical gardens. Another location with six plants was found in 2001. In 2003 the number of wild-growing individuals was given as 16, at that time there were about 50 in culture.
In the Red List of Threatened Species of the International Union for Conservation of Nature and Natural Resources , Mellissia begoniifolia is classified as " critically endangered (CR) " ("threatened with extinction").
Systematics
In the phylogenetically based systematics of the nightshade family by Richard Olmstead (2007), the genus is classified in the Withaninae within the subfamily Solanoideae. As early as 1999, leaves from the newly discovered individuals were sent to the Royal Botanic Garden Edinburgh for phylogenetic studies . The following research showed that Mellissia is related to the genus Withania . Since only two species of the genus Withania were included in the investigations, it is not certain whether the genus status of Mellissia is justified, but morphological differences such as the solitary flowers, the dry fruits and the black seeds suggest this. Contrary to this, however, Armando Hunziker , for example, reckons the species as Withania begonifolia (Roxb.) Hunz in his systematics of the nightshade family . et Barboza to the Withania .
Botanical history
The species was first described in 1815 by William Roxburgh under the name Physalis begonifolia after he had observed plants of the species during his stay on St. Helena from June 17, 1813 to March 1, 1814. They grew in abundance in the southeast of the island. The publication for the first description of the species was the last publication by Roxburgh, he died a few days after the manuscript was sent in. As early as 1843, Joseph Dalton Hooker suspected that the plant was extinct. However, when he described his own monotypical genus for the species in 1867, he described the status of the occurrence as "very rare, possibly already extinct". The independent genus was described by Hooker, as he did not attribute the plant to the bladder cherries ( Physalis ), but saw it close to the genus Withania , from which, in his opinion, it differs mainly through the crooked calyx and the shape of the crown. The generic name chosen by Hooker honors John Charles Melliss , who wrote a book about the island, including a description of the flora, in the 1860s as the representative of the English Crown on St. Helena. Melliss himself mentions in a work from 1875 that the species can still be found in the southeast of the island, but is already very rare. Since no type specimen was named in the original description of the species by Roxburgh , a herbarium document of a specimen collected by Roxburgh, which is in the herbarium of the Natural History Museum in London, was set as the lectotype . At the same time, in accordance with the rules of the International Code of Botanical Nomenclature (ICBN), the incorrect spelling of the epithet begonifolia used by Roxburgh was corrected to begoniifolia .
swell
Individual evidence
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ^ Martin Staniforth: St. Helena Boxwood saved . In: Kew Scientist ( Memento of the original from July 4, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 710 kB) , issue 16, October 1999. Page 8.
- ^ R. Cairns-Wicks: Mellissia begoniifolia . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed April 13, 2008.
- ^ Richard G. Olmstead and Lynn Bohs: A Summary of Molecular Systematic Research in Solanaceae: 1982-2006 . In: DM Spooner et al. (Ed.): Solanaceae VI: Genomics Meets Biodiversity , ISHS Acta Horticulturae 745, June 2007. ISBN 978-90-6605-427-1 .
- ↑ Armando T. Hunziker: The Genera of Solanaceae. ARG Gantner Verlag KG, Ruggell, Liechtenstein 2001. ISBN 3-904144-77-4 . Pages 264-270.
literature
- Michael F. Fay, Vanessa E. Thomas and Sandra Knapp: 602. Mellissia begoniifolia . In: Curtis's Botanical Magazine , Volume 24, Number 4, Pages 243-250. November 2007. doi : 10.1111 / j.1467-8748.2007.00601.x
Web links
- Mellissia begonifolia at arkive.org : pictures and descriptions.
