Apostasioideae

Neuwiedia griffithii

The Apostasioideae are a subfamily of the orchid family ( Orchidaceae). With only 17 species in two genera, it represents the smallest of the five subfamilies of this plant family dar. same time are gathered in their styles as the original of all orchids.

Features

All representatives of Apostasioideae are small perennial, herbaceous plants. The roots have no velamen. The leaves are spirally arranged along the slender stems. In the bud, the leaves are rolled, the leaf blade is Plikat. There is no separating tissue between leaf and shoot.

The inflorescences of Apostasioideae are branched terminally and simple or razemös. The flowers are spirally on the shoot, they are small and white, yellowish to yellow, sometimes ' upside. The bracts are relatively large and leaf-like foliage. The petals are available in two threefold circles, the specialization of a petal as labellum is weak ( Neuwiedia ) or absent ( Apostasia ). The ovary is inferior and dreikammerig. The narrow style ends in a scar that has three identically shaped stigma lobes. There are two or three fertile stamens present. The median stamen can be fully trained, reduced, atrophied to a barren Staminodium or omissions. The stamens are united at the base with one another and with the stylus. The oblong anthers contain the powdery pollen, the individual pollen grains are not glued together. The fruits are mostly capsule fruits, but rarely also similar to beer. They contain numerous plump seeds, about 300 microns in size and provided with a hard seed coat.

There were chromosome numbers of 2n = 48 in Apostasia and found 2n = 96 in Neuwiedia, Okada concludes a basic number of x = 12 The chromosomes are very small.

In some species takes place self-pollination, while others are pollinated by bees out loose due to vibration in the flower pollen.

Distribution and habitat

The types of Apostasioideae are found exclusively in Asia from Nepal, South China and Japan to New Guinea and in the far north of Queensland, Australia. They grow there in always humid climates in forests that are highly 200-2200 m.

System

Although the internal systematics of the two genera and their relationship to each other was mostly undisputed, the taxonomic position of the subfamily has been widely discussed. Mainly controversial is the question whether the Apostasioideae should actually be incorporated into the family of orchids or should be regarded as a separate family or Apostasiaceae Neuwiediaceae. Molecular genetic studies support the inclusion in the Orchidaceae and confirm the relationship between the two genera. A position as a sister taxon to all other orchids is discussed.

• Apostasia flower
• Neuwiedia flower