Laelia (orchids)

from Wikipedia, the free encyclopedia
Laelia
Laelia anceps

Laelia anceps

Systematics
Order : Asparagales (Asparagales)
Family : Orchids (orchidaceae)
Subfamily : Epidendroideae
Tribe : Epidendreae
Sub tribus : Laeliinae
Genre : Laelia
Scientific name
Laelia
Lindl.

The genus Laelia the family of orchids (Orchidaceae) was established in 1831 by the English botanist John Lindley established and comprises approximately 23 valid species. These are native to Central and South America. The lay people grow epiphytically or lithophytically , depending on the species .

description

Laelia includes small, herbaceous , perennial plants. The individual rungs are densely packed or with a little distance from a creeping, slightly woody rhizome . The roots are surrounded by a five to ten cell layer thick Velamen radicum . The stem axis is thickened to pseudobulbs . These are rounded to club-shaped, smooth or furrowed lengthways, surrounded by rapidly drying lower leaves . The pseudobulbs consist of several internodes , mostly these are all thickened, in some species the lowest ones are not thickened, so that the pseudobulb sits on a short stalk. At the upper end of the pseudobulbs there are one to three leaves . The leaf blade is oval to narrowly lanceolate, fleshy or leathery and rigid, green with occasional reddish tones. The end is pointed or blunt, the leaf base is wedge-shaped, without a petiole, there is a separating tissue between the shoot and the leaf.

Laelia gouldiana

The inflorescence is a terminal cluster . The flowers are arranged in two lines or spirals, sometimes densely packed at the end of the inflorescence. In some species are found on the bracts Nektarien . The ovary is club-shaped, with six ribs lengthways, smooth or warty, scaly, sticky. The flowers are resupinated in some species , not in others. They are big and colorful: pink, violet, yellow, white and brown tones also occur. The petals are not fused together. The three outer ones are lanceolate to narrowly oval, often of thick, fleshy texture, widely spread out, the edges often wavy. Their outside may be a little sticky or scaly. The lateral inner petals are usually slightly wider and less fleshy than the outer petals. Here, too, the edge can be wavy. The lip is articulated to the column at the base , the blade is three-lobed, with the side lobes usually folded upwards around the column. The anterior lobe is expanded or bent downward. In the middle there is a colored spot and some longitudinal calluses. The edges of the lip can be wavy, on the outside, as with the other two inner petals, there is a central, longitudinal groove. The column is curved, widening in the shape of a club towards the front, semicircular in cross section. At the base it forms a small depression with the lip and the base of the ovary, which does not contain any nectar. The stamen is bent down in relation to the column axis, the column surrounds the stamen like a hood with a one- to three-tooth tissue (clinandrium). The stamen contains eight waxy, yellow, unevenly shaped pollinia , which are connected by stalks (caudiculae). The pollen is organized in tetrads, the pollen grains have no opening (inaperturat). The scar sits across the column axis and is oval, triangular or heart-shaped. The separating tissue between the stamen and stigma (rostellum) is clearly protruding and forms an adhesive disc (viscidium). The capsule fruit is oval, stalked, furrowed lengthways. Parts of the inflorescence stick to the tip of the fruit.

The scent and color attract bees and bumblebees as pollinators. Xylocopa , Trigona and Bombus have been observed, and honey bees also visit the flowers, but are too small to pollinate them. The insects land on the spreading front part of the lip and crawl between the lip and the column into the flower, where the pollinia stick to them.

The chromosome number for most species is 2n = 40. Higher numbers of 2n = 41 or 2n = 42 were rarely counted, for Laelia anceps also 2n = 60 and 2n = 80.

distribution

The Laelia species are distributed from Mexico in the north through Central America and the Caribbean to Brazil and Bolivia in the south. They occur from sea level up to altitudes of 3000 meters. The climate of their place of growth is characterized by a dry period.

The genus probably spread towards South America from a Central American origin.

Systematics and botanical history

Laelia autumnalis , illustration from Edwards's botanical register
Inflorescence of Laelia marginata or Laelia gloriosa , one of earlier than Schomburgkia species designated
Laelia speciosa

Within the subfamily Epidendroideae , the genus Laelia is classified in the tribe Epidendreae and there in the subtribe Laeliinae . Laelia is closely related to Domingoa , Homalopetalum, and Nageliella .

For a long time, the scope of the genus was completely different: it contained numerous South American species and had a disjoint distribution between Central and South America. The genus was held together mainly by the number of pollinia as a common feature. More recent studies place the South American species formerly known as Laelia in the genus Sophronitis (or as an alternative to Cattleya ). The rest of the species found in Central America are closely related to some of the plants previously known as Schomburgkia . The transfer of this Schomburgkia to Laelia was proposed as early as 1941, but was only confirmed by DNA tests.

The following alphabetical list includes the species names accepted as valid by the scientists at Kew Gardens , London.

See also

literature

  • Alec M. Pridgeon, Phillip Cribb , Mark W. Chase: Genera Orchidacearum. Volume 4/1: Epidendroidae (Part one). Oxford University Press, 2005, ISBN 0-19-850712-7 , pp. 265-271.
  • Carl L. Withner : The Cattleyas and their relatives. Volume II: The Laelias. Timber Press, Portland 1998, ISBN 0-88192-161-0 .
  • Carl L. Withner: The Cattleyas and their relatives. Volume III: Schomburgkia, Sophronitis, and Other South American Genera. Timber Press, Portland 1993, ISBN 0-88192-269-2 .

Web links

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

Individual evidence

  1. ^ Cássio van den Berg et al. (2000): A phylogenetic analysis of Laeliinae (Orchidaceae) based on sequence data from internal transcribed spacers (ITS) of nuclear ribosomal DNA. In: Lindleyana. Volume 15, No. 2, pp. 96-114 ( semanticscholar.org PDF).
    Cássio van den Berg, et al .: A phylogenetic study of Laeliinae (Orchidaceae) based on combined nuclear and plastid DNA sequences . In: Annals of Botany . tape 104 , no. 3 , 2009, ISSN  0305-7364 , p. 417-430 , doi : 10.1093 / aob / mcp101 , PMID 19423551 , PMC 2720643 (free full text).
  2. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y Rafaël Govaerts (Ed.): Laelia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 9, 2020.