Thứ Bảy, 20 tháng 4, 2013

Miltonia

Miltonia, abbreviated Milt. in the horticultural trade,[1] is an orchid genus formed by nine epiphyte species and eight natural hybrids inhabitants of the Brazilian Atlantic Forest, one species reaching the northeast of Argentina and east of Paraguay. This genus was established by John Lindley in 1837, when he described its type species, Miltonia spectabilis. Many species were attributed to Miltonia in the past, however, today, the species from Central America and from cooler areas on northwest of South America have been moved to other genera. Miltonia species have large and long lasting flowers, often in multifloral inflorescences. This fact, allied to being species that are easy to grow and to identify, make them a favorite of orchid collectors all over the world. Species of this genus are extensively used to produce artificial hybrids.
Despite the fact that Miltonia is now a well established genus, most of its species were originally classified under other genera as Cyrtochilum, Oncidium, Odontoglossum, and Brassia. All were discovered between 1834 and 1850 with the exception of M. kayasimae, discovered only in 1976.
These epiphytic orchids occur from Central to Southern Brazil down to Argentina. These orchids have two leaves, arising from a pseudobulbs, covered with a foliaceous sheath. The inflorescence consists of waxy, nonspurred flowers. The lip is large and flat and lacks a callus at its base. They possess a footless column with two hard pollinia. The flowers have a delicate, exotic scent, some compare to that of roses.
They are named after Charles Wentworth-Fitzwilliam, 5th Earl Fitzwilliam, formerly Viscount Milton, an English orchid enthusiast.
The species in this genus are sometimes confused with the pansy orchids, but it is the other miltoniopsis orchids that have flowers that closely resemble the pansy. Almost everyone except for the most serious orchid hobbyists use these names interchangeably, which may cause confusion.
Miltonia looks more like oncidiums than the real pansy orchids. The most "pansy-like" a miltonia can get is the species Miltonia spectabilis. Taxonomists are debating whether to put miltonia into the oncidium genus because of the many connections between the two.
Miltoniopsis is the pansy orchid with huge showy flowers. They grow in cooler climates and are more challenging to grow than miltonias.
This genus forms with Miltoniopsis a hybrid genus xMilmiltonia J.M.H.Shaw.

Species

Miltonia cuneata
This is the hardest to grow among all Miltonia species, however, as all the others are very easy, this one is not really difficult. This is the one species that needs cooler conditions.
Miltonia kayasimae
This was the last species to be described and is the rarest one, having been found just a couple of times in São Paulo State, in Brazil.
The species of Miltonia show many differences to each other are very easy to identify, therefore, just the most evident differences are mentioned here; more details are given on individual species articles. The species are presented here according to their morphology and this order keeps no correspondence with phylogenetic relationships.
Regarding vegetative morphology Miltonia moreliana and Miltonia spectabilis can be immediately separated from the rest because their much flatter pseudobulbs, longer rhyzome and inflorescences completely covered by flattened bracts that bear only one highly flat flower. These are the species with largest flowers in the genus. They are closely related and usually are recognized because the flowers of M. moreliana usually have dark purple petals and sepals and the lip of a lighter bright purple while M. spectabilis has very light purple or white petals and sepals and a purple veined labellum, however, the real technical difference among the species is on the proportions of their segments which are much wider. Despite colors are often mentioned to identify species they are not accepted by taxonomy as enough to establish distinct species by themselves.[18] All other Miltonia species have similar vegetative appearance and only can be positively identified by their flowers.
Three species are unique: Miltonia flavescens has the most narrow flowers, almost star shaped, with all segments of straw color with some purple bots on the base of petals and sepals which are more intense on the labellum almost forming stripes;[2] Miltonia candida is the only species with a labellum that embraces the column in a way that reminds the Cattleya species;[28] Miltonia russelliana is the less showy of Miltonia species because its sepals and petals do no really open, being always bent over the column, revealing only the lighter tip of its purple labellum.[9]
Miltonia regnellii shows the widest flower color variation among all Miltonia species; they can vary from white to yellow, pink and lilac with labelli also varying from white to dark purple. The flowers open in succession and slightly resemble the ones of M. spectabilis although much smaller. They actually are the Miltonia species with the smallest flowers.[13]
Miltonia kayasimae and Miltonia cuneata are somewhat similar and possibly are closely related, both have straw color petals and sepals almost entirely covered by large brown stains and white labelli, however, they show different proportions on the flowers segments. M. kayasimae has much wider petals and sepals and smaller labellum which, moreover, has a larger and more salient and complex entirely purple callus on its base which is delicate, more straight and simple, and just occasionally purple dotted on its apex on M. cuneata.[19]
Miltonia clowesii has the same color pattern of M. russelliana with light yellow greenish brown sepals and petals completely covered with large darker dots or stains and labellum of bright purple at the base and lighter apex, however here they are whiter. On the other hand, M. clowesii flowers' pointed segments are larger and wide opened making it resemble a spider.[29]

Natural hybrids

Miltonia × bluntii
This is the natural hybrid of M. spectabilis and M. clowesii.
Considering its limited number of species, it is surprising that eight natural hybrids of Miltonia are currently known, a number that almost equals the number of species and also implies that the most important pollinator of the majority of the species possibly is the same. As the crossing of two species uses to produce variable plants most of these hybrids have been described more than once and some have three or four synonyms. M. spectabilis is the species which has produced the largest number of hybrids, five: Miltonia × bluntii when crossed with M. clowesii, Miltonia × cogniauxiae with M. regnellii, Miltonia × flava with M. flavescens, Miltonia × leucoglossa with M. candida and Miltonia × rosina with M. cuneata,[3] furthermore it is possible there is also one with M. moreliana, which has not yet been described because M. moreliana itself was earlier considered a variety of M. spectabilis.
M. candida, besides the hybrid already mentioned with M. spectabilis, also produced two others: Miltonia × binotii with M. regnellii and Miltonia × lamarckeana with M. clowesii.[3] The remaining hybrid, Miltonia × peetersiana used to be considered a synonym of M. × bluntii but because M. moreliana is now a species distinct from M. spectabilis it is its hybrid with M. clowesii, which has entirely purple flowers instead the one with light brown petals and sepals.[30]
  • Miltonia × bluntii Rchb.f. (1879) (= Miltonia clowesii × Miltonia spectabilis) (Brazil)
  • Miltonia × cogniauxiae Peeters ex Cogn. & Gooss. (1900) (Miltonia regnellii × Miltonia spectabilis) (Brazil)
  • Miltonia × cyrtochiloides Barb.Rodr. (1877) (Miltonia flavescens × Miltonia spectabilis) (Brazil)
  • Miltonia × lamarckeana Rchb.f. (1885) (Miltonia candida × Miltonia clowesii) (Brazil)

Culture

Despite being easy to grow, Miltonia species tend to be subject to spots on their thin leaves, generally caused by fungi proliferation and normally, when exposed to the amount of light they need to a full bloom, their foliage gets a bit too yellow-colored, although they should never be exposed to full sunlight. Finding the right balance of light exposure to avoid yellow leaves but still produce nice blooming is important and with some precautions the grower will succeed. They are not terribly sensitive to temperature, but they do vary according to their species make-up and origin; M. cuneata being one that grows cooler and M. moreliana the warmer growing, but all species under intermediate temperature with at least 10°C of variation between day and night. Despite the fact that they exhibit a rest period after blooming, Miltonia always need to be watered, and more abundantly during active growth and blooming. they need at least 65% relative humidity and good ventilation all the time. Moderate weekly fertilizing with a balanced formula is beneficial during active growth. They may be potted in a compost of half-chopped Sphagnum, peat, and some medium sized lumps of charcoal, or mounted on plaques of vegetable fiber, however if mounted they will need more frequent waterings.[31]

Intergeneric hybrids

  • xAliceara (Brassia x Miltonia x Oncidium)
  • xAspodonia (Aspasia x Miltonia x Odontoglossum)
  • xBakerara (Brassia x Miltonia x Odontoglossum x Oncidium)
  • xBeallara (Brassia x Cochlioda x Miltonia x Odontoglossum)
  • xBiltonara (Ada x Cochlioda x Miltonia x Odontoglossum)
  • xBlackara (Aspasia x Cochlioda x Miltonia x Odontoglossum)
  • xBrilliandeara (Aspasia x Brassia x Cochlioda x Miltonia x Odontoglossum x Oncidium)
  • xBurrageara (Cochlioda x Miltonia x Odontoglossum x Oncidium)
  • xCharlesworthara (Cochlioda x Miltonia x Oncidium)
  • xColmanara (Miltonia x Odontoglossum x Oncidium)
  • xCrawshayara (Aspasia x Brassia x Miltonia x Oncidium)
  • xDegarmoara (Brassia x Miltonia x Odontoglossum)
  • xDerosaara (Aspasia x Brassia x Miltonia x Odontoglossum)
  • xDuggerara (Ada x Brassia x Miltonia)
  • xDunningara (Aspasia x Miltonia x Oncidium)
  • xForgetara (Aspasia x Brassia x Miltonia)
  • xGoodaleara (Brassia x Cochlioda x Miltonia x Odontoglossum x Oncidium)
  • xMaunderara (Ada x Cochlioda x Miltonia x Odontoglossum x Oncidium)
  • xMilpasia (Aspasia x Miltonia)
  • xMilpilia (Miltonia x Trichopilia)
  • xMiltada (Ada x Miltonia)
  • xMiltadium (Ada x Miltonia x Oncidium)
  • xMiltarettia (Comparettia x Miltonia)
  • xMiltassia (Brassia x Miltonia)
  • xMiltistonia (Baptistonia x Miltonia)
  • xMiltonidium (Miltonia x Oncidium)
  • xMiltonioda (Cochlioda x Miltonia)
  • xMorrisonara (Ada x Miltonia x Odontoglossum)
  • xNorwoodara (Brassia x Miltonia x Oncidium x Rodriguezia)
  • xOdontonia (Miltonia x x Odontoglossum)
  • xRodritonia (Miltonia x Rodriguezia)
  • xSauledaara (Aspasia x Brassia x Miltonia x Oncidium x Rodriguezia)
  • xSchafferara (Aspasia x Brassia x Cochlioda x Miltonia x Odontoglossum)
  • xSchilligerara (Aspasia x Gomesa x Miltonia)
  • xSegerara (Aspasia x Cochlioda x Miltonia x Odontoglossum x Oncidium)
  • xVanalstyneara (Miltonia x Odontoglossum x Oncidium x Rodriguezia)
  • xVuylstekeara (Cochlioda x Miltonia x Odontoglossum)
  • xWithnerara (Aspasia x Miltonia x Odontoglossum x Oncidium)

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