Pure white water crowfoot
| Pure white water crowfoot | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Pure white water crowfoot ( Ranunculus ololeucos ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Ranunculus ololeucos | ||||||||||||
| J.Lloyd |
The pure white water crowfoot ( Ranunculus ololeucos ), also called pure white buttercup , is a species of the buttercup family (Ranunculaceae). This rare species belongs to the species group water buttercup ( Ranunculus aquatilis agg.) And is threatened with extinction in Germany. This species is also endangered within Central Europe .
description
The pure white water buttercup is a perennial, evergreen aquatic plant . The plant forms about three centimeters large, three-part floating leaves on the upper part of the stem. It is rooted in shallow water that is 30 to 60 centimeters deep. Adapted to life under water, the plant has robust, finely divided, hair-shaped water leaves in addition to the floating leaves. The leaf tips are not on one level, but are kidney-shaped to circular on a long stem. The leaves are longer than the distance between the stem nodes and reach a maximum of 10 centimeters. The plant forms roughly circular stipules , more than 2/3 of which are fused with the petiole.
The long flower stalks arise from the axils of the floating leaves. The sepals are 3.5 to 4.5 millimeters long, bent back and sometimes have blue tips. The oblong, egg-shaped, 7 to 15 millimeters long, pure white sepals seem obsolete. The flower generally forms 15 to 20 stamens , but there are also between 10 and 25 stamens. The nectar leaves are longer than 6 mm and the nectar glands appear crescent-shaped. The flowering period is May to June.
16 to 30 close-knit bald nuts are formed per flower. When immature, the fruits are hairy.
The species is diploid and has the number of chromosomes 2n = 16.
Distribution and ecology
The pure white water crowfoot is native to the temperate latitudes of Europe up to altitudes of around 700 meters. Its main area of distribution is in southern and western Europe from Portugal and Spain to northwestern Germany; outside of Europe it does not occur. In Germany there are only stocks in Lower Saxony , Bremen and North Rhine-Westphalia . Here you can find them in shallow water areas (30 to 50 cm depth) in nutrient-poor clear waters ( heather ponds ) of the Pleistocene sand areas. It is a character species of Ranunculetum ololeuci from the Hydrocotylo-Baldellion association. Not only in Germany, but also in the rest of Europe, it rarely occurs.
This species needs sunny to partially shaded places in moderately warm, nutrient-poor waters. Their presence indicates an extreme maritime climate with frequently changing water levels and soils that are poor in nitrogen. They can be found in ponds and ditches outside of cities, mainly in small to larger groups on the banks of the river.
The flowers are pollinated by insects or by self-pollination of the hermaphrodite flowers. The plant uses the spread of water to multiply .
ingredients
Like all other Ranunculus species, the pure white water crowfoot is poisonous.
Danger
In Germany this species is classified as “critically endangered”. There are only residual deposits in Lower Saxony, Bremen and North Rhine-Westphalia. It has already expired in Saxony. The portfolio development continues to decline. Since the species has the status of outpost character here and the area share in Germany is less than 10%, Germany's responsibility for the conservation of the species is only designated as "medium".
A further decline of the less competitive species can only be countered by maintaining open shallow water zones, preventing further drainage and avoiding further acidification of this area. However, the species was always rare because of the strong connection of the species to Pleistocene sand landscapes.
Systematics
There are a number of synonyms for the pure white water crowfoot ( Ranunculus ololeucos J.Lloyd ) . These are, with their respective references:
- Batrachium ololeucon / os (Lloyd) Bosch - Prodr. Fl. Batav., 1: 6 (1850)
- Ranunculus paucicarpus Arv.-Touv. - Essai Pl.Dauphiné (1871)
- Ranunculus lusitanicus Freyn - Flora, 63: 24 (1880) - Consp. Fl. Eur., Suppl., 1:10 (1883)
Sources and further information
The article is mainly based on the following documents:
Individual evidence
- ↑ Jaakko Jalas, Juha Suominen: Atlas florae europaeae . Volume 8 (Nymphaeaceae to Ranunculaceae). Page 209, Helsinki 1989. ISBN 951-9108-07-6
- ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 418 .
- ^ HE Weber: On the distribution and sociology of the pure white buttercup (Ranunculus ololeucos LLOYD) in Central Europe. - Osnabrücker Naturwissenschaftliche Mitt. 14: 157–166, Osnabrück. 1988
Web links
- Pure white water crowfoot. In: FloraWeb.de.
- Pure white water crowfoot . In: BiolFlor, the database of biological-ecological characteristics of the flora of Germany.
- Distribution in the Netherlands [1] (Dutch)
- Thomas Meyer: Data sheet with identification key and photos at Flora-de: Flora von Deutschland (old name of the website: Flowers in Swabia )
- Profile at the State Office for Nature, Environment and Consumer Protection in North Rhine-Westphalia
- Photos by JK Lindsey