Drosera amazonica
| Drosera amazonica | ||||||||||||
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| Scientific name | ||||||||||||
| Drosera amazonica | ||||||||||||
| Rivadavia , A. Fleischm. & Vicent. |
Drosera amazonica is a carnivorous plant belonging to the genus sundew ( Drosera ). The species, known only from Brazil, was first described in 2009.
description
Drosera amazonica is a perennial, herbaceous plant and forms a small, unbranched stem up to 10 cm high that is covered with dried up leaves from the previous season.
The stipules are paper-like, torn and divided into 5 segments fringed to the base. These segments are 0.1 mm long at the base, with the outer segments being slightly longer than the inner (about 1.5 to 2 mm). The inner segments are approx. 1 mm long.
The catch leaves are arranged in rosettes and hairless. Only at a young age are the leaves covered with sessile, transparent glands or with short, pressed, red or white hairs about 0.5 mm long. The petioles are hairless, 5 to 10 mm long, 1 to 2 mm wide, taper evenly to the leaf blade and the edges are slightly bent back. The leaf blades are spatulate to obovate, 2.5 to 5 mm long and 1 to 3 mm wide.
The single flowers are sessile or short-stalked and provided with bracts . Stem, bracts, pedicel and sepals are covered with short, pressed, about 0.5 mm long, red or white hairs. The peduncle and the lower part of the sepals are also covered with yellowish, transparent and short-stalked glands. The flower stem is short, 1 to 3.5 mm long, approx. 0.5 mm thick and upright in the flower, but bends downward in the fruit. The support sheet is awl-shaped or thread- shaped with a pointed tip, 1 to 2 mm long and 0.1 to 0.5 mm long. The flower stalk is 0.5 to 1 mm long and 0.5 mm thick. The 5 egg-shaped sepals are awl-shaped , pointed, 2.5 to 4 mm long and up to 1 mm wide in the middle. The calyx is bell-shaped and spreads at the fruit time. The 5 white petals are elongated, with a pointed to rounded tip, 5 to 6 mm long and 0.5 mm wide at the base and the tip and 1.2 to 2 mm wide at the widest point. The 3 styluses are dissected at the base and up to 2 mm long. The ovary is almost spherical and 1 mm in diameter. The plant has 5 stamens . The anthers are white, the filaments 2 to 2.5 mm long, 0.1 mm thick and the pollen yellow.
The seeds are ovate to spherical, 0.2 to 0.5 mm long, 0.2 to 0.3 mm wide, black and finely pitted.
Distribution, habitat and status
The distribution of Drosera amazonica is limited to two known populations in northern Brazil . The species is known from some collections about 100 km upstream from Manaus , along the Igarapé Cachoeira , a tributary of the Cuieiras River , which in turn empties into the Rio Negro . This habitat can be found in the "Parque Estadual do Rio Negro Setor Sul", an area that is relatively well protected from clearing. Another population is located about 450 km north of this region in the "Viruá National Park" and grows there together with Drosera capillaris .
The habitat of Drosera amazonica is an open savannah, dominated by grasses and sedges, and occasional trees and bushes. It thrives there on white quartz sand, which is flooded seasonally or in heavy rain. The soil is very acidic and extremely poor in nutrients and consists of either deep sand sediment or shallow soils with sandstone outcrops. The species forms large populations with many individual plants standing close together.
ecology
The flowers smell sweet. After flowering, the very short flower stalk bends downwards so that the ripe seed pods open downwards and the seeds are only distributed on the ground directly under the mother plant. The fine surface structure of the seeds traps air bubbles through capillary effects and thus gives them buoyancy. Therefore a spread through water ( nautochory) is assumed.
Systematics
The name " amazonica " refers to the biogeographical region in which this species is endemic , namely the northern Amazon basin in the Brazilian states of Amazonas and Roraima. Drosera amazonica is a relatively newly discovered species. In 1998, Fernando Rivadavia examined herbarium specimens of a previously undetermined Drosera species that were collected between 1961 and 1992. In 2006 he was able to determine the origin of the collections and to find the plants. In 2009 the species was described together with Alberto Vicentini and Andreas Fleischmann .
literature
- Fernando Rivadavia, Alberto Vicentini, Andreas Fleischmann : A new species of Sundew (Drosera, Droseraceae), with water-dispersed seed, from the floodplains of the Northern Amazon Basin, Brazil. In: Ecotropica. Vol. 15, 2009, ISSN 0949-3026 , pp. 13-21 .