Drosera stolonifera
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Drosera stolonifera is a carnivorous plant from the sundew family(Droseraceae). The species found in southwestern Western Australia belongs to the so-called " tuberous drosera", a group of sundew that forms tubers as persistent organs.
description
Drosera stolonifera is a perennial , herbaceous plant that grows from a red, kidney-shaped tuber up to 10 millimeters long and 15 millimeters wide, around which brown, paper-like covers lie as remains from previous years. The subterranean runners reach a length of 15 centimeters, aboveground runners resting on the substrate are rarely missing, are 1 to 1.5 millimeters thick and up to 10 centimeters long, and under good conditions daughter bulbs form on them. The two or three, rarely unbranched, 10 to 15 centimeter high stems stand half upright from a down-to-earth rosette. All of the leaves, petioles, stems, and flower stems are covered with tiny glands.
The plant has three different leaf shapes, two of them in the rosette and one on the stems. The upper side of all leaf blades is covered at the edge with somewhat longer, centrally shorter catching tentacles. The rosette is sparsely leafed. Your lowest leaves are stalked, the stem reaches a length of 4.5 to 5 millimeters, is flattened (1.5 to 2 millimeters) and broadened (2.5 to 3 millimeters). The leaf blades are wedge-shaped, 4 to 5 millimeters long and 1.5 to 2 millimeters wide. The spreading of the upper leaves of the rosette are transversely elliptical, 3 to 4 millimeters long and 5.5 to 7 millimeters wide. The leaves on the stem are arranged in three to four whorls per stem and are increasingly more upright towards the tip, resulting in a conical habit. They are stalked, the stalk reaches a length of 5 to 10 millimeters, has a longitudinal groove on the top and is 1 to 1.6 millimeters wide. The leaf blades are kidney-shaped, 2.5 to 3.5 millimeters long and 4 to 5.5 millimeters wide.
Flowering time is from September to October. The inflorescence axes carry two to three branched umbrella panicles and arise from the rosette at the base, but occasionally also in smaller and less flowered form from the leaf axils on the upper part of the stem axis . The main inflorescence is 15 to 20 centimeters long and has 12 to 20 flowers. The flower stalks are 7 to 12 millimeters long. The sepals are egg-shaped and pointed, black dotted and reach a length of 3.5 to 5 millimeters and a width of 1.7 to 3 millimeters. The petals are inverted ovoid and slightly notched at the tip. Their basic color is white, they are 7.5 to 8 millimeters long and 4 to 5 millimeters wide. The five stamens are between 3 and 4 millimeters long, the filament is white, the anthers and pollen are yellow. The green ovary is approximately round, almost 1 millimeter long and has a diameter of around 1.3 millimeters in the flowering period. The three styluses are white, around 1.5 millimeters long and divided into many sections, which are partly whorled and partly upright in the center of the whorl. The scars are simply shaped at the end of the stylus.
The capsule fruit is 1.5 millimeters long with a diameter of 2 millimeters and contains around twelve black, cup-like shaped seeds, which are 0.5 to 0.6 millimeters long, 0.4 to 0.5 millimeters wide and with net-like, irregularly grooved Surface are provided.
Distribution, locations, endangerment
The species is native in southwestern Western Australia in swampy heathland south of Perth to Pinjarra . The locations are all waterlogged, peaty and sandy, it occurs in association with myrtle heather ( Melaleuca ), occasional bush fires lead to mass blooms. The species is common in its range and is therefore not considered endangered.
Systematics and research history
The type specimens were collected by Carl von Hügel at the Swan River in 1833 and first described by Stephan Friedrich Ladislaus Endlicher in 1837 . The type epithet means something like "runners" and refers to the ability of the species to form such.
Drosera stolonifera is part of the section Stoloniferae in the subgenus Ergaleium , of which it is a type species. Drosera stolonifera is closely related to Drosera purpurascens .
Since Ludwig Diels set up the first sub-taxon in 1906 with the incorporation of Drosera humilis as a subspecies, numerous other varieties and subspecies have been set up. After numerous of these new descriptions, especially in the 1980s and 1990s, Allen Lowrie and NG Marchant revised the complex in 2005 and raised all sub-taxa to species rank. Due to a formal error (Lowrie and Marchant forgot the page number of the basionyma required by Article 33.4 of the ICBN ), the new combination Drosera monticola is invalid and has not been added since then, so that in addition to the nominate subspecies, as before
- Drosera stolonifera subsp. monticola
exists as a sub-taxon.
According to Lowrie, two forms that are not formally described can be distinguished within the nominate form, namely one from the marshland and one from the hill country, the latter becoming significantly redder with increasing age of the foliage.
proof
- ↑ a b c d e f g h i Allen Lowrie: A taxonomic revision of Drosera section Stolonifera (Droseraceae), from south-west Western Australia. In: Nuytsia . Vol. 15, No. 3, 2005, pp. 355-393 .
