Ranunculus rionii

Rions water crowfoot (Ranunculus rionii )

Rions water crowfoot (Ranunculus rionii ), also known as Tender water crowfoot, is a plant of the family Ranunculaceae ( Ranunculaceae ). This species belongs to the species group of weißblütigen water Ranunculus (Ranunculus aquatilis agg. ) And is relatively unknown because it is often confused with the Haarblättrigen water crowfoot.

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Description

Vegetative characteristics

Rions water crowfoot is an annual or perennial, evergreen water plant. The plant does not form floating leaves and reaches lengths of up to about one meter. It is rooted in up to two meters of water. The provided with air chambers, bare, flood stems grow upright or lying down.

Adapted to life under water the plant has finely divided, hair-like submerged leaves. Out of the water fall along these brush-like. The lower leaves are short- stalked water while the upper sit on the stem. The water leaves are polygonal and three-piece to the base. The leaf sections are not parallel, but strive stiff apart, they are short-stemmed and fork repeatedly in three parts. The thread-like leaf lobes spread out on all sides limply. The leaves are usually longer than the distances between the stem nodes. The plant forms ovate stipules that have grown to more than 2/ 3 with the petiole.

Flowers and Fruit

The long flower stems arise in relation to the blade root and are one to one and a half times as long as the opposite leaf. At the upper part of the stalk spring a few flowers and protrude above the water surface. The five-fold flower has a diameter of about one centimeter, this is in comparison to other types of small water crowfoot. The base of the flower is hairy. The flower is. The five green, bare sepals are about 2.5 millimeters long. The five white at the base, yellow petals do not overlap. Their shape is obovate with a rounded tip and measure about 4 × 2 mm. The bloom developed about 15 stamens, while also nectar leaves are formed. The nectar leaves are Roehrig, have pear-shaped mouths and are without a cover scale. The flowering period is May to August.

For each flower, a cylinder- shaped head with 50 to 100 standing close together, only 1 to 1.2 mm long and 0.6 to 0.8 mm wide, oval, always bare nutlets is formed. These have four to ten transverse wrinkles.

Other properties

This type is the type Haarblättriger water crowfoot (Ranunculus trichophyllus ) are very similar, has as a distinguishing factor but a bald head with fruit 50 to 100 fruits. When the fruits Haarblättrigen water crowfoot head is spherical, the nutlets are 1.4 to 1.9 mm long and 0.9 to 1.2 mm wide and always hairy on his back against the beak towards bristly. Nevertheless, the species is little known and is often confused. It also has a large variability of leaf traits.

The chromosome number is given as 2n = 16.

Distribution and ecology

Rions water crowfoot is native to the temperate regions of Eurasia at altitudes of about 700 meters. In South Africa and in western North America, he was brought. In Europe one finds scattered him and often isolated in southwest Germany, the Czech Republic, Lower Austria, Slovenia, and Western Hungary before. South of the Alps, it grows only in northern Italy, and in South East Europe it is found in the Dalmatian and Adriatic coast of Slovenia to Greece and slightly more common in Romania and in the Crimea.

Rions water crowfoot grows on moderately nutrient-rich, neutral to basic, clayey and muddy ( never gravelly ) pond bottoms. He settled in a sunny, clear, in the summer of strongly heated and partially or completely drying pools and ponds. In Germany he is also in lakes, ditches and backwaters of rivers before low flow.

The low competitive plant found mainly in locations such as pioneer newly established mines in clay, sand or gravel soils. Sometimes the species includes its life cycle within a few weeks. Pollination of flowers carried by insects or by self-pollination of hermaphrodite flowers. They spread by birds, usually together with other hydrophytes. Many sites are correspondingly along the major bird migration routes. The seeds can apparently persist in the soil long and remain viable. Like all other Ranunculus species Rions water crowfoot toxic.

In Switzerland and in other European countries, the species is on the Red List of endangered plant species.

System

For Rions water crowfoot (Ranunculus rionii Lagger ) there are a number of synonyms. These are, with their respective references:

• Ranunculus flaccidus var rionii ( Lagger ) Hegi - Ill. Fl. . Mitt -Eur, 3: 585 (1912 ) -
• Ranunculus trichophyllus subsp. rionii ( Lagger ) JAV. - Magyar Fl: 370 (1924) -.
• Batrachium trichophyllum subsp. rionii ( Lagger ) CDKCook - Mitt bot Munich, 3: 601 ( 1960)

Sources and further information

The article is mainly based on the following documents: