Aracamunia liesneri

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Aracamunia liesneri
Systematics
Family : Orchids (orchidaceae)
Subfamily : Orchidoideae
Tribe : Cranichideae
Sub tribus : Spiranthinae
Genre : Aracamunia
Type : Aracamunia liesneri
Scientific name of the  genus
Aracamunia
Carnevali & I. Ramírez
Scientific name of the  species
Aracamunia liesneri
Carnevali & I. Ramírez

The orchid Aracamunia liesneri - it is the only known species of the genus Aracamunia - is a small herbaceous plant that is only a few centimeters tall. It has only been found in the Cerro Aracamuni mountain range in southern Venezuela .

description

Aracamunia liesneri has a thin, creeping rhizome from which the shoots arise. The rhizome is covered with lower leaves that surround it, but are spaced apart and do not completely envelop it. Three to six roots arise at the base of the shoot . These are cylindrical, hairy and up to three inches long. The leaves are loosely shaped like a rosette at the base of the shoot. The leaf base embraces the stem and covers it completely. The oval leaf blade is five to nine millimeters long and three to four millimeters wide, slightly wavy on the edge, the tip of the leaf is pointed. In the leaf axils sits a structure that resembles the ligula in grasses: about four millimeters long and one millimeter wide, attached to the leaf base and standing upright. At the end there is a little head covered with multicellular, glandular hair. The function is unclear, Salazar notes, the anatomy of this structure is comparable to that of carnivorous plants.

The stem axis is leafed for about 1.5 centimeters in the lower area. About seven to eleven leaves are formed. The lower ones pass, so that there are around four to five left at the time of flowering. The ligula-like structures remain on the stem axis, even if the associated leaf has already withered. The stem axis continues over the leafy part as a 3.5 to 4.5 centimeter long inflorescence axis. This is hairy and covered with three lanceolate bracts. There are three to six flowers in the upper quarter . Each flower sits in the axilla of a bract, which is similar in shape to the bracts on the stem, but is three to seven millimeters long and two millimeters wide, but slightly smaller. The flowers are tubular, white, not resupinated and are obliquely upright. They measure seven to eight millimeters in length, of which about two millimeters to the ovary omitted. The three outer petals are three-quarters fused together, slightly hairy on the outside. The sepal facing away from the stem is also largely fused with the two narrow tepals and with the column at the base . The other two sepals form a small bulge at the bottom. The lip is narrow-oval, about six to a millimeter in size, abruptly narrowing at the base with two appendages pointing backwards. The tip of the lip is finely haired, the sides lie close to the sides of the column. This is straight, narrow club-shaped and is about 4.5 millimeters long with a diameter of just under one millimeter. The two-chambered stamen lies on top, the column surrounds it with a narrow edge (clinandrium). The scar sits on the underside of the column, the separating tissue between the scar and the stamen (rostellum) forms a straight surface at the end of the column. There is also a round adhesive body (Viscidium).

distribution

Aracamunia liesneri is only known from a single mountain massif in southern Venezuela, the Cerro Aracamuni. The plants grow there at altitudes of around 1500 meters. They occur in cushions of moss on the edge of streams, in the shade of closed forests.

Systematics and botanical history

The plants were first collected in 1987 by Liesner and Delascio and scientifically described in 1989 by Germán Carnevali and Ivón Ramírez . The name of the genus, Aracamunia , refers to the place where it was found, the Cerro Aracamuni. The specific epithet liesneri honors Ronald Liesner, who collected the plants.

The genus Aracamunia is placed within the orchid family in the tribe Cranichideae and there in the sub- tribus Spiranthinae . The authors of the first description suspect close relatives in the genus Eurystyles . Salazar, however, points out the strong similarity with Helonoma and suspects that further studies could lead to an integration of Aracamunia liesneri in Helonoma .

supporting documents

The information in this article comes from:

  • Gerardo A. Salazar: Aracamunia . In: Alec M. Pridgeon, Phillip Cribb, Mark W. Chase, Finn Rasmussen (eds.): Genera Orchidacearum. Orchidoideae (Part two). Vanilloideae . tape 3/2 . Oxford University Press, New York and Oxford 2003, ISBN 0-19-850711-9 , pp. 168-170 .
  • Germán Carnevali, Ivón Ramírez: Orchidaceae . In: JA Steyermark, BK Holst (ed.): Flora of the Venezuelan Guayana - VII. Contributions to the flora of Cerro Aracamuni, Venezuela. Annals of the Missouri Botanical Garden . tape 76 , 1989, pp. 962-964 ( botanicus.org [accessed April 13, 2008]).

Further information