Zannichellia palustris
Swamp Pond thread ( Zannichellia palustris)
The perennial perennial marsh pond thread ( Zannichellia palustris ) is a submerged living ( submerged ) aquatic plant of the family of pondweed plants. He is on a plant both purely male and purely female flowers from ( monoecious ). These are always under water. There is both a water pollination of flowers and a water spread of the drupes. The plant can also reproduce vegetatively by stolons form or by fragmentation. Individual sections are separated so partly independently viable.
Features
The Swamp Pond thread is up to 50 cm long and is highly branched. Its stems rooted at the nodes, in the upper part of this is flutend. The linear shaped leaves have an open side at the bottom of the leaf sheath ( Axillarstipel ), which is often referred to as Ochrea. The threadlike leaves are never wider than 0.5 mm and are located two lines or almost constantly against the stem. The very small single flowers are always under water. The male flowers standing alone and have no shell. They contain one or two deformed stamens. the female flowers, however, have a cup-shaped, glass-like perianth, which usually has free ovary and shield-shaped scars. The stylus is about 0.5 mm long. The approximately 1 mm in size, seated, beaked stone fruits are often 2 or 5 together and are short-stalked.
Ecology
The Swamp Pond thread is an annual, summer annual, end -rooted, submerged aquatic plant.
The flowers are monoecious. It takes place underwater pollination. The nude male flowers are distinguished by ( mostly ) one seated dust bag. The fibrous layer of the pollen sac wall is degenerate. The spherical pollen germinates mostly in the storage pouches on short threads and " flooded " by the funnel- shaped scar of female flowers that usually enclose 4Stempel in membranous envelope. Bloom time is from May to September.
The fruits are 1- samige stone fruits, beaked by an extension and sickle- shaped; they are laid as a floating or Velcro fruit. Fruit ripening from July to October.
Vegetative propagation is done by rooting at nodes, Stem bzw.durch the crawling on the ground rhizome.
Subspecies
There are currently three different subspecies, which, however, both the site conditions and vegetative some can be very difficult to separate.
- Zannichellia palustris subsp. palustris
- Zannichellia palustris subsp. pedicellata
- Zannichellia palustris subsp. polycarpa
Occurrence
The Swamp Pond thread is common in the temperate zones of the northern and the southern hemisphere. It grows in meso-to eutrophic standing or flowing water bodies such as lakes, ponds, rivers, streams or ditches. He is somewhat salt- tolerant and therefore also occurs on the North Sea and Baltic Sea coast. The plant can also tolerate a certain degree of contamination. In the southern provinces of the marsh pond thread is rare to find. In some states it is even on the Red List of vascular plants. He is the Kennart the plant association Zannichellietum palustris and has its main occurrence in association Najadetum intermediae and the Association Ranunculion fluitantis.