''Epidendrum radicans'' is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

. Common names include ground-rooting epidendrum, fire-star orchid, rainbow orchid, and reed-stem epidendrum.''Epidendrum radicans''.
Royal Botanic Gardens, Kew. It is a common roadside weed at middle elevations in

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

. It is a crucifix orchid, often confused with many other members of the section ''Schistochila'', including '' E. calanthe'', '' E. cinnabarinum'', '' E. denticulatum'', '' E. erectum'', '' E. fulgens'', '' E. ibaguense'', '' E. imatophyllum'', '' E. incisum'', '' E. schomburgkii'', '' E. secundum'', and '' E. xanthinum'', among others. The diagnostic characteristic of ''E. radicans'' is its tendency to sprout roots all along the length of the stem; other crucifix orchids only produce roots near the base. Additionally, ''E. radicans'' flowers are

resupinate Resupination is derived from the Latin word ''resupinus'', meaning "bent back with the face upward" or "on the back". "Resupination" is the noun form of the adjective "resupine" which means "being upside-down, supine or facing upward". The word " ...

, unlike the members of the ''Epidendrum secundum'' complex, ''E. fulgens'', and many other crucifix orchids. ''E. radicans'' also differs from ''E. secundum'' by bearing no nectar in the flower.

Description

''E. radicans'', like other members of subgenus '' Amphiglottium'', is a sympodial orchid which grows stems which do not swell into pseudobulbs and are covered with imbricating sheaths, produces a terminal inflorescence covered at its base by close imbricating sheaths, and produces a

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

to the

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member ...

to its apex. The lip of ''E. radicans'' is trilobate, as with the other members of section ''

Schistochila ''Schistochila'' is a genus of liverwort in family Schistochilaceae. It contains the following species (but this list may be incomplete): * '' Schistochila macrodonta'' W.E. Nicholson * ''Schistochila undulatifolia'' Piippo * ''Schistochila lehma ...

'', with the lacerate lobes which are typical of the subsections '' Carinata'' and '' Tuberculata''. ''E. radicans'' differs from the other lacerate ''Schistochila'' by producing roots from most of the stem. ''E. radicans'' seeds are quite small, at 320 seeds per milligram. The chromosome number of an individual collected in

Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...

has been determined as 2n = 60. Other reported chromosome numbers for ''E. radicans'' include 2n = 40, 2n = 57, 2n = 62, and 2n = 64Fábio Pinheiro, Samantha Koehler, Andréa Macêdo Corrêa, Maria Luiza Faria Salatino, Antonio Salatino & Fábio de Barros. "Phylogenetic relationships and infrageneric classification of ''Epidendrum'' subgenus ''Amphiglottium'' (Laeliinae, Orchidaceae)", ''Plant Systematics and Evolution'' published online 25 September 2009. Springer Wien. https://doi.org/10.1007%2Fs00606-009-0224-2

Taxonomic placement

A biochemical examination (Pinheiro & al., 2009) of the lacerate ''Schistochila'' subsections encompassing

plastid The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosymbiotic cyanobac ...

nucleotide sequence data from the ''trn''L—''trn''F regions, Amplified Fragment Length Polyorphism ( AFLP) data, and somatic chromosome number for 30 individuals in three of the thirteen recognized species of ''E''. subsect. ''Tuberculata'' and twenty individuals in eleven of the twelve recognized species of ''E''. subsect. ''Carinata'', including ''E. radicans'', has suggested that perhaps ''E.'' subsect. ''Carinata'' should be replaced with three subsections: an "Atlantic" subsection, an "Andean" subsection, and a monotypic subsection for ''E. radicans''.

Ecology

''E. radicans'' is part of a complex of several orange-flowered, weedy species (including ''

Asclepias ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to human ...

spp''.) that are unrelated but ecologically similar. Species within this group share pollinators as well as habitat, and are believed to exhibit what is known as

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

, where unrelated species "converge" upon similar physical characteristics as a result of similar evolutionary pressures. Paulette Bierzychudek studied pollinator behavior in the apparent complex consisting of ''E. radicans'', ''

Asclepias curassavica ''Asclepias curassavica'', commonly known as tropical milkweed, is a flowering plant species of the milkweed genus, ''Asclepias''. It is native to the American tropics and has a pantropical distribution as an introduced species. Other common nam ...

'', and ''

Lantana camara ''Lantana camara'' (common lantana) is a species of flowering plant within the verbena family (Verbenaceae), native to the American tropics. It is a very adaptable species, which can inhabit a wide variety of ecosystems; once it has been introduc ...

'', but could not find clear evidence that floral mimicry was affecting pollination rates for any of the three species.

Notes

References

* Pansarin, E. R., and Amaral, M. C. E.: "Reproductive biology and pollination mechanisms of ''Epidendrum secundum'' (Orchidaceae). Floral variation: a consequence of natural hybridization?" ''Plant Biology'' 10 (2008) 211-219 *Paulette Bierzychudek: "''Asclepias'', ''Lantana'', and ''Epidendrum'': A Floral Mimicry Complex?" ''Biotropica'', 13, 2, Supplement: Reproductive Botany (Jun., 1981), pp. 54–58, published by The Association for Tropical Biology and Conservation

External links

{{Taxonbar, from=Q5382801 radicans Orchids of Ecuador