Epidendrum

Epidendrum nocturnum

The genus Epidendrum of the orchid family (Orchidaceae) comprises more than 1,500 plant species that occur in South and Central America. It is mostly evergreen, perennial, epiphytic growing plants. They represent a significant part of the neotropical orchid flora.

Description

The species of the genus Epidendrum form ( sympodium ) on a creeping rhizome at intervals sprouts with limited growth. Some species grow monopodial. The shoot axis is often long, slender and recalls in its proportions to a reed or bamboo stem. Occasionally it is also thickened cigar-shaped or shaped to roundish pseudobulbs. The roots arise from the rhizome, rare along the stem axis, they are smooth and fleshy, surrounded by about three to seven cell layers thick velamen.

The leaves sit in two rows on the shoot, depending on the type is per shoot only one sheet exists or he is densely foliated. The leaf base surrounds the scion tubular. Between leaf and leaf base there is usually a separation fabric. The leaf shape varies from about linear lanceolate to broad oval. The leaves are leathery -fest often, but sometimes paper- thin or fleshy thickened to terete. Some species have a reddish drawing on the otherwise green leaves. Both sides or just the bottom of the sheet is covered with trichomes.

The inflorescence appears frequently from a spathe at the top of the rung. But there are also species with lateral inflorescences or the rhizome bears alternately a leafy and flowering shoot. Species growing monopodial, the inflorescence usually form the side, but also monopodially growing species having a terminal inflorescence and thus limited lifetime of the plant ( Semelparity ) occur. The shape of the inflorescence ranges from flowered umbels up to and panicles, occasionally a further flowering stem develops from an inflorescence in the next growing season. The flowers are not always ' upside, they are spirally or two lines on the flowering shoot. The most common flower color is pale green to white, it come out blue but all other colors before. Often the flowers produce scent, often only at certain times of day. The sepals and petals are not fused and mostly wide open. See the inner petals of the outer three similar, they are usually narrower, in some species only thready. The lip is adherent to the edges of the column along its entire length, rarely partly or entirely free. Lip and column to form a tube, this nectary continues up into the ovary. The lip is easy or three to vierlappig. On the lip is often centered a callus. The column is straight or curved, rarely it forms a pedestal or a sac-like protrusion at the base along with the lip. The stamen is located on the top or at the end of the column and has two or four pole lines. The two are combined by a pedicel to a pair. The scar has a central and two distinct lateral lobes. The rostellum is a slit along the column, it produces a semi-liquid adhesive ( Viscidium ).

The fertilization is made by insects that try to lip -column tube to reach the nectar ( keyhole flower) and get it glued pollinia or transferred to them sticky pollinia on the stigma. The few pollinators that could be observed were mostly butterflies or moths, but also bees, flies, wasps, and in some species hummingbirds ensure pollination. Many species produce no nectar and deceive the pollinators.

The capsule fruit is oval, sometimes pear-shaped or almost round. The seeds are numerous and small, with a diameter of 500 to 1000 uM. There are also species whose seeds have up to six millimeters wide appendage and thus belong to the largest orchid seeds.

The chromosome number 2n = 40 is usually

Dissemination and locations

The species of the genus Epidendrum are located throughout most of the Neotropics. The northernmost occurrence lie with Epidendrum magnoliae in the subtropical southeastern United States, Argentina is in the south yet been reached. The evolutionary origin of the genus could be in Central America, since there are more representatives of virtually all intra- generic groups before.

Most species are epiphytes humid or seasonally dry forests. Different species have focused on the colonization of branches in the crown of the Interior, in the outer, sunny area of ​​the tree crown or trunk. Only Zweigepiphyten does not exist in the genus. Some species live in humus accumulations in crotches or are preferably found in the nests of arboreal ants. Members of this genus is also available in plantations and orchards. Although the greatest diversity of species is found in humid cloud forests, there are various adaptations to dry growing places: deciduous species as well as those with succulent leaves or sprouts.

Terrestrial sites are colonized by a small number of species. There are specialists for highly ruderal sites that happen to landslides, sand dunes or along roadsides. This species bloom after one or two years before they are replaced by higher vegetation again. Other terrestrial Epidendrum species are found in the grasslands of the Andes ( Páramos ) or on the tepui called mesas.

System

Within the subfamily Epidendroideae the genus Epidendrum in the tribe Epidendreae and there in the subtribe Laeliinae is classified. Epidendrum is closely related to Barkeria, Caularthron and Orleanesia.

Botanical history

Carl Linnaeus named all known him epiphytic orchids Epidendrum, which means something like " on the tree ". The designated Linnaeus species is expected today on various genres.