Brachystele
Brachystele bracteosa
Brachystele is a genus of the orchid family ( Orchidaceae). It consists of about twenty species of herbaceous plants that are native to Central and South America. They grow terrestrial, usually on rather dry locations.
Description
The species of the genus Brachystele are small perennial plants. The roots are fleshy and fusiform or fusiform - thickened stalked. Plants produce a rosette of leaves from a few leaves, sometimes only a leaf is present. They are oval shaped to lanceolate and run at the end to a point. The leaf base runs to narrow into a dimly remote petiole. In its heyday, the leaves are usually already wilted.
The racemose inflorescence appears terminal. The inflorescence axis is glandular- hairy, sometimes hairy in the lower part bare and just above. It is enclosed by tubular, glabrous bracts, usually sometimes enlarged thin and translucent leaf-like foliage with darker veins, the lower bracts. The ovary is cylindrical, slightly twisted and bent slightly so that it attaches pointing upwards on the stem, the flower however protruding horizontally. The flowers are close to many crowded together at the end of the inflorescence axis, usually they are distributed on all sides, sometimes slightly einseitswendig. The flowers are small, 'upside, greenish, white or yellowish, sometimes fragrant. The petals are tubular inclined together, only their tips are sometimes repulsed. The sepals are free, just the two side are fused to their asymmetric base a short distance to each other; where they form with the extension of the column ( pillar ) a bulge (mentum ). The spatulate petals haftem to the dorsal sepal. The lip is sessile or with a short pedicle ( " spiked " ) basis. The edges are thickened at the base of two rearward nectar glands lamina of the lip is coated. The column is short, becoming thicker at the top, slightly elongated at the base of the joint with the ovary ( pedestal ). The scar consists of two surfaces, which may be close to each other or separated clearly. The rostellum ( separation between scar tissue and stamen ) is soft and very short, undivided, it is visible only as a little raised line on the stigmatic surfaces. In the middle of the rostellum is a membrane- spanning pit ( fovea ), this is ripped in herbarium material and the rostellum then appears in two parts. The stamen is roundish - oval to heart-shaped, it contains two yellow, compressed - club-shaped pollinia. These are divided along deep, they adhere to a small, round viscid disc ( Viscidium ). The fruit capsules are inversely - ovate.
Occurrence
Brachystele is distributed in three areas in Central and South America. In the north they settled an area that extends from Mexico through Central America to northern South America with Venezuela and Guyana. In the southeast, the spread along the Atlantic coast of Brazil with Uruguay enough to Argentina. In the southwest of the genus colonized a strip along the Pacific coast from Peru to Chile. The species occur from sea level to 2300 meters above sea level before. They grow in rather sunny, open situations such as grasslands, savannas, thorn bush, deciduous woods or clearings in evergreen forests.
Systematics and botanical history
Brachystele is classified within the tribe Cranichideae in the subtribe Spiranthinae. Outwardly, it resembles the genera Sauroglossum and Odontorrhynchus, Pelexia also shows similarities in details of the flower.
Brachystele was first described by Rudolf Schlechter 1920. He grouped twelve already known orchid species under this genus name. Type species is Brachystele unilateralis. The name comes from the ingredients brachys, " short" and stele, "pillar" together.
The following 21 species are counted to Brachystele:
- Brachystele arechavaletae ( Kraenzl. ) Schltr.
- Brachystele bicrinita Szlach.
- Brachystele bracteosa ( Lindl. ) Schltr.
- Brachystele burkartii M.N.Correa
- Brachystele camporum ( Lindl. ) Schltr.
- Brachystele Chlorops ( Rchb.f. ) Schltr.
- Brachystele cyclochila ( Kraenzl. ) Schltr.
- Brachystele delicatula ( Kraenzl. ) Schltr.
- Brachystele dilatata ( Lindl. ) Schltr.
- Brachystele guayanensis ( Lindl. ) Schltr.
- Brachystele luzmariana Szlach. & R.González
- Brachystele maasii Szlach.
- Brachystele oxyanthos Szlach.
- Brachystele pappulosa Szlach.
- Brachystele pedicellata ( Cogn. ) Garay
- Brachystele scabrilingua Szlach.
- Brachystele subfiliformis ( Cogn. ) Schltr.
- Brachystele tamayoana Szlach. , Rutk. & Mytnik
- Brachystele unilateralis ( Poir. ) Schltr.
- Brachystele waldemarii Szlach.
- Brachystele widgrenii ( Rchb.f. ) Schltr.