Mesadenella

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

Mesadenella is a genus from the family of the orchid (Orchidaceae). It contains ten species that are native to tropical America.

description

The Mesadenella species are herbaceous plants, the individual species vary in size, they grow terrestrially or lithophytically . Some species form an underground rhizome , the roots emerge in clusters, they are fleshy, spindle-shaped, glabrous or hairy. The leaves are in a basal rosette. They are petiolate or wedge-shaped at the base. The leaf blade is oval to inverted-lanceolate. The leaf surface is sometimes lightly spotted or covered by a network of dark-colored leaf veins.

Illustration of Mesadenella atroviridis (Fig. II, right)

The terminal, racemose inflorescence is hairy in the upper area. Some bracts partially envelop it. The numerous flowers are small and inconspicuous, their color is white, whitish-green and brown. The hairy bracts are lanceolate. The hairy also ovary is sessile hardly twisted and facing obliquely upwards. The sepals are hairy on the outside, they form a tube, only the tips are slightly curved outwards. The upward-pointing (dorsal) sepal is lanceolate, the lateral sepals are slightly oblique at their base, run down at the base of the column and form a depression (mentum) with it. The petals lie against the dorsal sepal and adhere with their inner edges there, their tips are free. The lip is clearly narrowed (nailed) at the base, with two arrow-shaped nectar glands pointing backwards. The spread of the lip is runny, the sides are bent upwards and adhere to the column . The column is short, club-shaped, on the underside with a longitudinal groove, there hairy, at the base with a curved foot. The scar is bilobed and V-shaped. The stamen is narrow-oval in outline, the base is rounded, at the front it ends with a point. It contains the lanceolate to club-shaped pollinia that hang on a common adhesive disc (Viscidium). The separating tissue between the stamen and the stigma (rostellum) is stiff, somewhat cartilaginous, elongated, pointed. The capsule fruit is oval.

Occurrence

Mesadenella occurs in tropical America from Mexico in the north to southern Brazil, northern Argentina and Paraguay. The species grow in the shade of forests, in ever-humid climates or with a short dry season. They are often found on river banks or in locations that are temporarily flooded. They occur up to an altitude of 800 meters.

Systematics and botanical history

Illustration of Mesadenella cuspidata (left, under the synonym Stenorrhynchos esmeraldae )

Mesadenella is classified within the tribe Cranichideae in the subtribe Spiranthinae . The genus was described by Pabst and Garay in 1952 . The name is a diminutive of Mesadenus and refers to the similarity of the pollinarium of the two genera. The lectotype is Mesadenella esmeraldae , a synonym of Mesadenella cuspidata .

The genus Mesadenella is closely related to the genera Eltroplectris and Sacoila . While Balogh saw Mesadenella in 1982 only as a section of a broad genus Stenorrhynchos , Szlachetko further subdivided Mesadenella by separating Mesadenella atroviridis as a separate genus Garaya .

The genus Mesadenella contains the following species :

Mesadenella angustisegmenta Garay : It occurs from Venezuela to Ecuador.
Mesadenella atroviridis (Barb.Rodr.) Garay : It occurs in southeastern Brazil.
Mesadenella bicordata Szlach. & Kolan. : The species first described in 2014 occurs in Colombia.
Mesadenella cuspidata (Lindl.) Garay (Syn .: Stenorrhynchos esmeraldae (Linden & Rchb.f.) Cogn. ): It occurs in tropical South America.
Mesadenella longipetiolata Szlach. & Kolan. : The species first described in 2014 occurs in Colombia.
Mesadenella meeae R.JVAlves : It occurs in the Brazilian state of Minas Gerais.
Mesadenella peruviana Garay : It occurs in Peru.
Mesadenella tonduzii (Schltr.) Pabst & Garay : It occurs from southern Mexico to Costa Rica and in Brazil.
Mesadenella variegata D.E.Benn. & Christenson : It occurs in Peru.

literature

Leslie A. Garay: 225 (1). Orchidaceae (Cypripedioideae, Orchidoideae and Neottioideae) . In: Gunnar Harling, Benkt Sparre (ed.): Flora of Ecuador . tape 9 , 1978, ISSN 0347-8742 , p. 237-238 .
Leslie A. Garay: A generic revision of the Spiranthinae . In: Botanical Museum Leaflets of Harvard University . tape 28 , no. 4 , 1982, pp. 334-335 .
Alec M. Pridgeon, Phillip Cribb, Mark W. Chase, Finn Rasmussen (Eds.): Genera Orchidacearum. Orchidoideae (Part 2). Vanilloideae . tape 3 . Oxford University Press, New York and Oxford 2003, ISBN 0-19-850711-9 .

Individual evidence

↑ Rafaël Govaerts (Ed.): Mesadenella. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew .
↑ ^a ^b Gerardo Salazar: Mesadenella . In: Genera Orchidacearum . Vol. 3, pp. 222-224.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Rafaël Govaerts (Ed.): Mesadenella. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved July 16, 2018.

Further information

List of orchid genera

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

[Kew-1] Rafaël Govaerts (Ed.): Mesadenella. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew .

[Salazar2003-2] Gerardo Salazar: Mesadenella . In: Genera Orchidacearum . Vol. 3, pp. 222-224.

[WCSP-3] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Rafaël Govaerts (Ed.): Mesadenella. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved July 16, 2018.