Brachystele
| Brachystele | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
_-_Edwards_vol_23_pl_1934_(1837).jpg)
Brachystele bracteosa , illustration |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Brachystele | ||||||||||||
| Schltr. |
Brachystele is a genus from the family of the orchid (Orchidaceae). It consists of about twenty types of herbaceous plants that are native to Central and South America. They grow terrestrially , mostly in rather dry locations.
description
The species of the genus Brachystele are small, perennial plants. The roots are fleshy and spindle-shaped or stem-spindle-shaped and thickened. The plants develop a rosette of leaves from a few leaves , sometimes only one leaf is present. They are oval to lanceolate in shape and taper to a point at the end. The leaf base tapers into an indistinctly separated petiole. At the time of flowering, the leaves are usually withered.
_-_Brachystele_guayanensis_(as_Spiranthes_guayanensis,_spelled_S._guyanensis)_-_Sarcoglottis_schwackei_(as_Spiranthes_schwackei).jpg)
The racemose inflorescence appears terminal. The inflorescence axis is hairy glandular, occasionally glabrous in the lower area and hairy only higher up. It is enclosed by tubular, hairless bracts , usually thin and translucent with darker veins, the lower bracts sometimes enlarged like leaves. The ovary is cylindrical, slightly twisted and slightly curved so that it attaches to the stem pointing upwards, but the flower protrudes horizontally. The flowers are too many densely packed at the end of the inflorescence axis, mostly they are distributed on all sides, occasionally slightly one-sided. The flowers are small, resupinated , greenish, white or yellowish in color, sometimes fragrant. The petals are tubularly bent together, only their tips are sometimes turned back. The sepals are free, only the two lateral sepals have grown together a short distance at their asymmetrical base; there they form a bulge (mentum) with the extension of the column (column base). The spatulate petals adhere to the dorsal sepal. The lip is sessile or with a short-stalked ("nailed") base. The margins are thickened at the base to form two nectar glands pointing backwards, the lip of the lip is hairy. The column is short, getting thicker at the top, slightly elongated at the base over the point of attachment to the ovary (column foot). The scar consists of two surfaces that can be close together or clearly separated. The rostellum (separating tissue between the stigma and stamen ) is soft and very short, undivided, it is only visible as a slightly raised line above the stigma surface. In the middle of the rostellum there is a membrane-spanned pit (fovea), this is torn in the herbarium and the rostellum then appears to be divided into two parts. The stamen is rounded-oval to heart-shaped, it contains two yellow, compressed-club-shaped pollinia . These are deeply divided lengthways, they adhere to a small, round adhesive disc (Viscidium). The capsule fruits are inverted egg-shaped.
Occurrence
Brachystele is common in three areas in Central and South America. In the north it populates an area that stretches from Mexico via Central America to the north of South America with Venezuela and Guyana. In the southeast the distribution extends along the Atlantic coast from Brazil via Uruguay to Argentina. In the southwest, the genus populates a strip along the Pacific coast from Peru to Chile. The species occur from sea level to 2300 meters above sea level. They grow in more sunny, open situations such as meadows, savannahs, thorn bush, deciduous forests 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 in 1920. He groups twelve previously known orchid species under this generic name. The type is Brachystele unilateralis . The name is made up of the components brachys , "short" and stele , "column".
The following 20 species are included in Brachystele :
- Brachystele arechavaletae (Kraenzl.) Schltr. : It occurs in Uruguay.
- Brachystele bicrinita Szlach. : It occurs in Brazil.
- Brachystele bracteosa (Lindl.) Schltr. : It occurs in Brazil and Paraguay.
- Brachystele burkartii MNCorrea : It occurs in Argentina.
- Brachystele camporum (Lindl.) Schltr. : It occurs from Brazil to northeast Argentina.
- Brachystele chlorops (Rchb.f.) Schltr. : It occurs from Bolivia to northwest Argentina.
- Brachystele cyclochila (Kraenzl.) Schltr. : It occurs in Brazil, Argentina, Paraguay and Uruguay.
- Brachystele delicatula (Kraenzl.) Schltr. : It occurs in Paraguay.
- Brachystele dilatata (Lindl.) Schltr. : It occurs from Peru and Brazil to Argentina.
- Brachystele guayanensis (Lindl.) Schltr. : It occurs from Mexico and Trinidad to tropical South America.
- Brachystele luzmariana Szlach. & R.González : It occurs in Mexico.
- Brachystele maasii Szlach. : It occurs in Colombia.
- Brachystele oxyanthos Szlach. : It occurs in Suriname.
- Brachystele pappulosa Szlach. : It occurs in Uruguay.
- Brachystele scabrilingua Szlach. : It occurs in Brazil.
- Brachystele subfiliformis (cogn.) Schltr. : It occurs in Brazil.
- Brachystele tamayoana Szlach., Rutk. & Mytnik : It occurs in Baja California .
- Brachystele unilateralis (Poir.) Schltr. : It occurs in Peru, Chile and Argentina.
- Brachystele waldemarii Szlach. : It occurs in Uruguay.
- Brachystele widgrenii (Rchb.f.) Schltr. : It occurs in Brazil and Argentina.
No longer counted in this genus:
- Brachystele pedicellata (Cogn.) Garay => Aspidogyne pedicellata (Cogn.) Meneguzzo
literature
- Leslie A. Garay: A generic revision of the Spiranthinae . In: Botanical Museum Leaflets of Harvard University . tape 28 , no. 4 , 1982, ISSN 0006-8098 , pp. 302-304 .
- Alec M. Pridgeon, Phillip Cribb, Mark W. Chase, Finn Rasmussen (Eds.): Genera Orchidacearum. Orchidoideae (Part 2). Vanilloideae . tape 3/2 . Oxford University Press, New York / Oxford 2003, ISBN 0-19-850711-9 , pp. 176-179 .
Individual evidence
- ↑ a b c d e f g h i j k l m n o p q r s t u v Rafaël Govaerts (Ed.): Brachystele. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved July 8, 2018.
