Chysis

Chysis laevis

The genus Chysis from the orchid family (Orchidaceae) consists of ten plant species that are common in Central and South America. They grow there as epiphytes in humid forests.

Description

From the rhizome of the Chysis species arise at short intervals the shoots. The roots are rich branched, hairy and surrounded by velamen. The shoots are pendulous, up to 45 centimeters long and slightly thickened towards the upper end, so that a cull or fusiform pseudobulb. At the bottom of the rung is surrounded by low membranous leaves, in the upper part are arranged in two rows of six to twelve leaves. The leaves are oval to broad - lanceolate, papery thin, folded along the numerous visible longitudinal nerves. At the base they go about in a leaf sheath that covers the shoot. A separating tissue between leaf and leaf base allows the leaves are discarded after one growing season.

One to three racemose inflorescences appear laterally from leaf axils in the lower part of the shoot. The inflorescences appear very early in the growing season, when the shoot and the leaves are not yet fully formed. The resupinierten flowers have a fleshy or waxy texture. The color is white, pink or yellow, often the petals are spotted and the lip wears colored markers. The three outer petals are broad oval, the inner narrower shape. The two lateral sepals are with an extension of the column ( " pedestal " ) grow together and form a " chin " at the bottom of the flower. The lip also relies on the column where it is three-lobed, the lateral lobes are wrapped around the column to the top. Centered on the lip is a three-to siebenkieliger callus. The column carries at the end opposite to the column axis down curved stamen. Eight pollinia ( four major and four minor) are available. They are held together by two oval, formed from anther tissue platelets. In some species, self-pollination takes place, here are the individual pollinia and platelet merged into a coherent mass which comes right after the bloom on the scar. The hexagonal capsule fruit still carries the maturity time the remains of the column.

Dissemination

The species of the genus Chysis have seen a proliferation of Mexico in the north, through Central America and the Andes of South America to Peru. They colonize altitudes of 500 to 1000 meters.

They grow as epiphytes in moist woods without a pronounced dry season. They often grow on the trunk of trees, so to quite shady places, rarely they are found on rocks.

Systematics and botanical history

The genus Chysis was described by Lindley in 1837 with the type species Chysis aurea. The genus name comes from the Greek χύσις Chysis = heap, meaning that appear merged the eight pollinia to a mass ( in self-pollinating species). Both morphologically and by means of DNA analysis are not particularly close relatives to identify. Even Rudolf Schlechter presented in 1926 for this genus own subtribes called Chysinae on (also Chysiinae written ). This is classified in the tribe Epidendreae, where they had a basal group, possibly the sister group to all other Epidendreae is.

The following species are known in this genus:

• Chysis addita Dressler, Mexico
• Chysis aurea Lindl., Panama, Venezuela, Colombia
• Chysis bractescens Lindl, Central America. Mexico, Belize, El Salvador, Guatematela
• Chysis bruennowiana Rchb.f. & Warsz. , Widespread from Costa Rica to Peru
• Chysis laevis Lindl., Central America
• Chysis orichalcea Dressler, El Salvador
• Chysis pluricostata Dressler, Panama
• Chysis tricostata Schltr. , Mexico, Costa Rica, Nicaragua
• Chysis violacea Dressler, Panama

Documents

• C. H. Dodson, C. A. Luer: Orchidaceae part 2 (Aa - Cyrtidiorchis ). In: G. Harling, L. Andersson ( eds.): Flora of Ecuador. 76, Botanical Institute, Göteborg University, 2005, ISBN 91-88896-51- X, pp. 216-218.
• Robert L. Dressler: Phylogeny and Classification of the Orchid Family. Cambridge University Press, 1993, ISBN 0-521-45058-6, pp. 187-188.
• Alec M. Pridgeon, Phillip Cribb, Mark W. Chase ( Ed.): Genera Orchidacearum. Epidendroideae ( Part one ). 2nd edition. 4/1, Oxford University Press, New York and Oxford, 2005, ISBN 0-19-850712-7, pp. 177-180.