Metteniusa
The Metteniusa are the only genus in the family of Metteniusaceae and includes seven species that are native to South America.
Description
Metteniusa are evergreen trees that reach a growth rate of 4 to 20 feet, their branches are korkporig, hairy young branches tomentose. The alternate standing, stalked leaves are entire. The petiole is grooved achszugewandt. On the surface the stomata achsabgewandten sit in cyclocytischer arrangement.
The axillary inflorescences are zymös and have two to four bracts and two to seventeen aktinomorphe, hermaphroditic flowers on. The five imbricate sepals are fused lying about a third at the base, pubescent tomentose on the outside of the bent-back and on the inside red tomentose hairy petals are fused, the crown is about 2 inches long.
The five around 0.8 inches dust bags are moliniform, the three branches have so similar to the wings of a windmill by increased connective away in the center, where they are anchored to the stamens. The pollen are tricolporate. The Upper constant ovary is unicompartmental, unusual is the location of the ovule at the top of the carpel ( placentation ). The large, thread-like stylus is glabrous, the stigma is punctiform.
The fruit is a drupe with woody endocarp fünfrippige. The seeds have plenty of white endosperm.
Dissemination
The species of the genus are found in Costa Rica, Peru, Ecuador, Colombia and Venezuela in the eastern Andes at altitudes 160-2000 m.
System
The Metteniusaceae be allocated to any order within the Euasteriden I, their exact systematic position is still unsettled.
The family contains only one genus with seven species:
- Metteniusa cogolloi Lozano
- Metteniusa cundinamarcensis Lozano
- Metteniusa edulis H.Karst.
- Metteniusa huilensis Lozano
- Metteniusa nucifera ( Pittier ) Sleumer
- Metteniusa santanderensis Lozano
- Metteniusa tessmanniana ( Sleumer ) Sleumer.
Botanical history
Genus and family were first described in 1859 by Gustav Karl Wilhelm Hermann Karsten, type species is Metteniusa edulis H.Karst. The genus name honors the botanist Georg Leipzig Mettenius. The exact systematic position of the genus was up to the present unclear, as the species was provided, inter alia, the Cardiopteridaceae and Icacinaceae, but the intuition as own family prevailed with Gustavo Lozano's monograph in 1988, which contributed to the knowledge of essential Metteniusa.
Molecular genetic studies have confirmed this classification and placed the family as an isolated basal taxon of a clade from Lippenblütlerartigen, nightshade -like, gentian -like and Raublattgewächsen and Vahlia. The next related but are the Oncothecaceae.
Evidence
- Polidoro Pinto, Gustavo Lozano (eds.): Flora de Colombia. Volume 11: Gustavo Lozano- C, Nubia B. de Lozano. Metteniusaceae. Universidad Nacional de Colombia, among others, Bogota 1988.