Skeptrostachys

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Skeptrostachys
Illustration of Skeptrostachys rupestris (Fig. I) and Skeptrostachys balanophorostachya (Fig. IV)

Illustration of Skeptrostachys rupestris (Fig. I) and Skeptrostachys balanophorostachya (Fig. IV)

Systematics
Order : Asparagales (Asparagales)
Family : Orchids (orchidaceae)
Subfamily : Orchidoideae
Tribe : Cranichideae
Sub tribus : Spiranthinae
Genre : Skeptrostachys
Scientific name
Skeptrostachys
Garay

Skeptrostachys is a plant genus in the family of orchids (Orchidaceae). The ten or so species are common in South America.

description

Vegetative characteristics

The Skeptrostachys species are perennial herbaceous plants . On a short rhizome the roots are in clusters, rarely also distributed along the rhizome. The fleshy roots are cylindrical, thickened, glabrous or hairy.

The leaves are distributed in the lower area of ​​the stem, rarely they form a basal rosette. When they bloom, they are often withered. The leaf shape is oval to lanceolate, the leaf base is wedge-shaped, there is no petiole. The leaf margins are slightly translucent.

Generative characteristics

The terminal, racemose inflorescence is hairy in the upper area. The inflorescence stem is covered by ciliate bracts . The green or red-brown bracts are often ciliate.

The numerous, close-together flowers are resupinated , fleshy, without fragrance, their color is white, light green, yellow or red. The hermaphrodite flowers are zygomorphic and threefold. The hairy ovary is oval to spindle-shaped and often slightly asymmetrical. The sepals are hairy on the outside, lie against each other and thus form a tube, their tips are slightly bent back. The upward-pointing (dorsal) sepal is hood-shaped, the lateral sepals are asymmetrical at their base and fused together for a short distance, so they form a bulge together with the column base. The petals lie against the dorsal sepal and adhere to it with their inner edges. The lip is sessile, at the base wedge-shaped with thickened edges (nectar glands), hairy differently on both sides. Seen from the side, the blade of the lip is curved in an S-shape. The sides are bent upwards and cling to the column , the lip ends rounded and with a wavy edge. The column is short, cylindrical and hairless, protruding at the base over the point of attachment on the ovary ("column foot"), this column foot fused a piece with the ovary, then a short piece free. The scar is semicircular to V-shaped, it stands parallel to the column or points slightly forward. The stamen is oval or lanceolate in outline, with a pointed tip. It contains the narrow, club-shaped, longitudinally furrowed pollinia that hang on a common, elongated adhesive disc (Viscidium). The separating tissue between the stamen and the stigma (rostellum) is stiff, pointed, narrowly triangular in shape, with two lateral teeth at the base.

The capsule fruit is obovate.

In Skeptrostachys paraguayensis a chromosome number of 2n = 46 was found, whereby one chromosome pair is significantly larger than all the others.

Locations

Skeptrostachys species occur at altitudes of up to 1600 meters. They colonize open grasslands, savannas and swamps.

Illustration of Skeptrostachys gigantea

Systematics, botanical history and distribution

The genus Skeptrostachys was established in 1982 by Leslie A. Garay . The generic name Skeptrostachys is derived from the Greek σκῆπτρον skeptron for "scepter" and στάχυς stachys , "ear", and refers to the appearance of the inflorescence. The type species is Skeptrostachys rupestris .

The genus skeptrostachys belongs to subtribe spiranthinae from the tribe cranichideae in the subfamily Orchidoideae within the family of Orchidaceae . The genus Skeptrostachys was split off from Stenorrhynchos . There are similarities to the genus Sacoila .

Skeptrostachys species are common in southeastern Brazil, as well as in neighboring Argentina, Paraguay and Uruguay.

There are about ten species in the genus Skeptrostachys :

literature

  • Leslie A. Garay: A generic revision of the Spiranthinae . In: Botanical Museum Leaflets of Harvard University . Volume 28, No. 4 , 1982, ISSN  0006-8098 .
  • Alec M. Pridgeon, Phillip Cribb, Mark W. Chase, Finn Rasmussen (Eds.): Genera Orchidacearum. Orchidoideae (Part 2). Vanilloideae . tape 3 . Oxford University Press, New York / Oxford 2003, ISBN 0-19-850711-9 .

Individual evidence

  1. ↑ a b c d e f g h i j k l Rafaël Govaerts (Ed.): Skeptrostachys. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Accessed March 31, 2020.
  2. ↑ a b c Leslie Garay: Skeptrostachys. In: A generic revision of the Spiranthinae . Cambridge Mass 1982, pp. 358-359.
  3. ↑ a b c d e f Gerardo Salazar: Skeptrostachys . In: Genera Orchidacearum. Volume 3. Oxford University Press, New York 2003, ISBN 0-19-850711-9 , pp. 256-257.
  4. ↑ Julio Rubén Daviña, Mauro Grabiele, Juan Carlos Cerutti, Diego Hernán Hojsgaard, Rubén Dario Almada, Irma Stella Insaurralde, Ana Isabel Honfi: Chromosome studies in Orchidaceae from Argentina . In: Genetics and Molecular Biology . tape 32 , no. 4 , 2009, ISSN  1415-4757 , doi : 10.1590 / S1415-47572009005000089 .

Web links

Commons : Skeptrostachys  - album with pictures, videos and audio files