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Stanhopea

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Stanhopea
Stanhopea insignis
Scientific classification
Kingdom:
Plantae
(unranked):
Angiosperms
(unranked):
Monocots
Order:
Asparagales
Family:
Orchidaceae
Subfamily:
Epidendroideae
Tribe:
Maxillarieae
Subtribe:
Stanhopeinae
Genus:
Stanhopea

J. Frost ex Hook. 1829
Species

See text.

Stanhopea (J. Frost ex Hook. 1829) is a genus of showy epiphytic Orchids from very wet forests in Central and South America that are highly prized in horticulture. The abbreviation used in horticultural trade is Stan. The genus is named for the 4th Earl of Stanhope (Philip Henry Stanhope) (1781-1855), president of the Medico-Botanical Society of London (1829-1837). These epiphytic, but occasionally terrestrial orchids can be found in damp forests from Mexico to NW Argentina. Their ovate pseudobulbs carry from the top one long, plicate, elliptic leaf.

It is noted for its complex and usually fragrant flowers that are generally spectacular and short-lived. Their pendant inflorescences are noted for flowering out of the bottom of the containers in which they grow, lending themselves to culture in baskets that have enough open space for the infloresence push through. They are sometimes called upside-down orchids.

In habitat, these plants predominantly grow as epiphytes in very wet forests in large tropical trees where the large main branches intersect the trunk and have formed crotches where twigs and woody forest litter have collected in fairly deep layers, with the plants growing partially buried in this material and flowering downwards through it. The areas these plants grow in tend to concentrate and funnel leaf and twig litter, and an upward inflorescence would at various times of the year become buried under debris falling from above, which resulted in downward, burrowing flower spikes being selected for over time. These plants and the debris piles they grow in tend to fall or be blown out of trees occasionally, and the plants are found terrestrially. Species of this genus all host wood devouring mycorhizzial fungi which supplement the plants nutrition by breaking down decomposing wood. Most of these species have a prolonged saprophytic stage in decomposing wood as seedlings before developing leaves and photosynthesis.

Many of these species and their close relatives are locally rare and critically endangered throughout their native ranges, and have never been common, with most of them widespread in distribution but with isolated local populations and the plants only infrequently encountered in habitat. The plants habits and appearance are very similar from species to species, and cannot be used to distinguish between various species. The only reliable indicators are the number of flowers produced, the color to a limited degree, and the floral structures.

Primitive Stanhopeas[1] Most Stanhopea flowers flash prominent, elegant horns on the epichile. The exception are the species; S. annulata, S. avicula, S. cirrhata, S. ecornuta and S. pulla. A second group have short or truncated horns, they include the species; S. candida, S. grandiflora, S. reichenbachiana, S. tricornis and the natural hybrid S. x herrenhusana. The structure of the labellum of this group is in general, not as complex as other members of the genus.

With most Stanhopea flowers lasting three days or less, the blooms must attract pollinators very quickly. These chemical attractants are generated in the hypochile, attracting the male euglossine bees to the flower. When the bee touches down on the flower, a great effort is made to collect chemical scent - he eventually slides on the waxy surface of the hypochile, gliding down on the slippery lip to exit the flower. The long column is touched in the process, resulting in the bee taking up pollinia at the very tip of the column. When the bee slides down another flower, the pollinia are deposited on the sticky surface of the stigma.

The plants have demonstrated in cultivation they are capable of self fertilization if cross pollination does not occur from another plant. Plants observed in habitat are self pollinated rather than cross pollinated 87% of the time by male euglossine bees since the bee will visit each flower in succession in his amorous attempts to collect as much scent as possible which he releases at mating sites with female bees. He collects and stores the scent in specialized sponge-like structures on his legs that absorb it. Why he does so is a mystery, as studies indicate the female bees do not demonstrate measurable attraction to the scent or even seem to differentiate between males carrying the scent and males that are not carrying it. Other males do seem to respond to it however, and it is theorized that the odor is used by males as a territorial display to intimidate competing males. These bee species are all solitary and live as solitary individuals and do not form eusocial colonies.

The flowers of these species evolved to last only a short span of days because they clearly did not need to last any longer for pollination to occur since a single bee typically will pollinate an entire plant, and the trap flower structure ensures that he does as he visits each flower. [2]

The majority of species are robust plants that grow readily in cultivation. For relatives of Stanhopea see Stanhopeinae and the closely related sister subtribe Coeliopsidinae..

Species

Stanhopea tigrina
Stanhopea oculata
Stanhopea graveolens

The type species is Stanhopea insignis.

Natural hybrids

  • Stanhopea × fowlieana (Stanhopea costaricensis × Stanhopea ecornuta) (Costa Rica)
  • Stanhopea × herrenhusana (Stanhopea reichenbachiana × Stanhopea tricornis) (Colombia)
  • Stanhopea × horichiana (Stanhopea ecornuta × Stanhopea wardii) (Costa Rica)
  • Stanhopea × lewisae (Stanhopea ecornuta × Stanhopea inodora) (Guatemala)
  • Stanhopea × thienii (Stanhopea annulata × Stanhopea impressa) (Ecuador)

Intergeneric hybrids

  • × Aciopea (Acineta × Stanhopea). Aciopea Guillermo Gaviria (Acineta erythroxantha × Stanhopea wardii) was registered Nov-Dec 2004 by Guillermo Gaviria-Correa (Colombia).
    • × Aciopea is abbreviated Aip..
  • × Cirrhopea (Cirrhaea × Stanhopea)
  • × Coryhopea (Coryanthes × Stanhopea)
  • × Stangora (Gongora × Stanhopea)
  • × Stanhocycnis (Polycycnis × Stanhopea)

Species

  • Stanhopea anfracta
    Stanhopea anfracta
  • Stanhopea annulata
    Stanhopea annulata
  • Stanhopea candida
    Stanhopea candida
  • Stanhopea cirrhata
    Stanhopea cirrhata
  • Stanhopea connata
    Stanhopea connata
  • Stanhopea costaricensis
    Stanhopea costaricensis
  • Stanhopea ecornuta
    Stanhopea ecornuta
  • Stanhopea embreei
    Stanhopea embreei
  • Stanhopea grandiflora
    Stanhopea grandiflora

Natural Hybrids

  • Stanhopea × horichiana
    Stanhopea × horichiana

References

  1. ^ http://autrevie.com/Stanhopea/Stanhopea_Primitives.html
  2. ^ The Orchids, Natural History and Classification, Robert L. Dressler. ISBN 0674875265
  • Rudolf Jenny (December 1993) "The Genus Stanhopea," in: Orchids 62(12):1270-1277
  • Rudolf Jenny (December 2003) "The Genus Stanhopea. Part 1: S. anfracta to S. napoensis," in: Caesiana no. 21, Supplement. 200 color photos, 160 p.
  • Jenny, R. (2004) "The genus Stanhopea: 2nd part, S. nigripes to S. xytriophora" Caesiana no. 22: 146-291.
  • Gerlach, G. (2004). "Die Subtribus Stanhopeinae. 6. Stanhopea". J. Orchideenfreund. 11 (1): 53–76. (in German)
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