Miltonia, abbreviated Milt in horticultural trade, is a small genus of the orchid family.
Miltonia species range starts on the area of Missiones in the northeast of Argentina and east of Paraguay and spreads north along the Brazilian mountains of Serra do Mar and its branches up to the State of Pernambuco on Brazilian northeast. They occupy mostly areas between 200 and 1,500 meters of altitude meters, however the majority of the species are more often found about 600 to 900 meters. Miltonia species can be found from shady areas inside the forest to areas more exposed to the sun, however never are under full sunlight; usually in ventilated places where they receive plenty humidity during the night and early morning. They are always epiphyte and, because they grow very fast, each pseudobulb originating two new growths every year, they soon form large colonies.
Miltonia russelliana and Miltonia flavescens are the ones with the widest dispersion and found at lower altitudes. M. flavescens is the only species that exists in countries other than Brazil and is also the one that spreads farther north. M russelliana range starts on Rio Grande do Sul and ends at Bahia State. M. regnellii is also widespread although does not go northern than Rio de Janeiro. M. moreliana is a species more common at lower altitudes and warmer areas existing from Rio to Pernambuco. Miltonia candida, Miltonia clowesii and Miltonia spectabilis are restricted to the four states of Region Southeast of Brazil. Miltonia cuneata is just from São Paulo and Rio and the one that grow at highest altitudes. M. kayasimae is the only species really rare; it has been found just a couple of times in a very restricted area close to Salesópolis, in São Paulo State. The mountains area between São Paulo and Rio de Janeiro, where almost all species do exist may be considered the center of distribution of Miltonia
These orchids have one or 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.
Miltonia species have large and long lasting flowers, often in inflorescences with several of them. Species of this genus are extensively used to produce artificial hybrids.
Miltonia are comparatively medium large orchid plants reaching about fifty centimeters height. They present subcaespitous growth, that means their pseudobulbs are not tightly packed but slightly spaced by a rhizome, that is longer than on caespitous plants, with length between two and five centimeters. Their roots grow along the rhizome in high numbers. They are white, comparatively thin, usually short and hardly branched. The rhizome is covered by dried imbricating sheaths which get increasingly larger at the base of pseudobulb becoming articulated foliar sheaths that partially cover them.
The pseudobulbs and leaves vary in color from yellowish bright light green to olive green depending on the species and to the amount of sunlight they are exposed to. They may be more oval and laterally highly flattened to slightly tetragonal and elongated and almost always bear two apical leaves. The leaves are narrow, flexible and hardly larger than three centimeters wide and forty long with the apexes rounded sometimes slightly pointed. Some species are about half of this size.
The inflorescence are one or two per pseudobulb, shoot from their bases behind the protecting sheaths. They are erect and never branched, often longer than the leaves, bearing from one to twelve moderately spaced flowers that open at the same time or in succession holding three or four opened all the time, when the older fades a new one opens. The older flowers of species with white lips that open in succession usually get yellower about the time the next flower opens although they still last one more week before fading.
Grow in intermediate conditions with moderate light during Summer, and more light during Winter. The pot medium should not dry out completely, but sufficient drainage is needed to avoid root rot. At all time mist the plants frequently, if possibly in the morning to mimic the morning dew of the natural habitat. Plants should be potted in a well drain medium such as medium fir bark.
The first species to be described, among the ones today classified under the genus Miltonia, was originally published by John Lindley, in 1834, as Cyrtochilum flavescens. In this description Lindley notices that the flowers of this species turn orange color when drying and, for some confusion regarding the origin of the species, attributes it to Mexico instead of Brazil. Two years later Lindley described another Miltonia species but, then, under the genus Oncidium, as O. russellianum in homage to Duke of Bedford. When describing this plant, Lindley considered it as a transition species pointing out that it was very different from the average Oncidium because of its purple colors and undivided lip.
In 1837, Lindley received from Mr. Loddiges and from George Baker two other specimens of a very distinctive new species. Recognizing then this should in fact be a new genus, he proposed the name Miltonia to it as a homage to Lord Fitzwilliam Milton, an English orchid enthusiast. Lindley states then that the limits between a number of Oncidiinae genera, Cyrtochilum, Oncidium, Odondoglossum, Brassia and Miltonia, at that time classified as Vandaea, were yet to be perfectly established; although closely related, the differences should possibly be: Oncidium has a column with two ears and labellum distinctively lobed; Miltonia has a column with two ears and an entire labellum partially united to the column base; Odontoglossum and Cyrtochilum have winged columns and entire labelli but the former has it partially united to the column; and Brassia does not have any appendages on the column. It is interesting to notice that despite Lindley described the genus Aspasia in 1833, which is the most closely related to Miltonia, both by flower and vegetative morphologies, he did not mention it on Miltonia description.
Three other Botanists were working with Miltonia species around the time Lindley described this genus. All recognized these plants should be classified under a new genus and, as communications were slower then, all proposed new genera: Knowles and Westcott also received also a plant of M. spectabilis and, just one month after Lindley, proposed for it the genus Macrochilus, calling the species Macrochilus fryanus; the other one was Rafinescque who, in 1838, decided that the Oncidium russellianum already described by Lindley in 1836 should be under another genus and created for it the genus Gynizodon. Both Macrochilus and Gynizodon are synonyms of Miltonia and no other species has ever been submitted to them.
As Miltonia species are common plants, comparatively large, with also large flowers of bright colors, that, moreover, are spread mostly over an area of early settlements in Brazil all species but one were already described in 1850; six of them by Lindley, M. regnellii by Reichenbach and M. moreliana by Achille Richard. Despite the early description of M. moreliana in 1848, and two other as M. rosea by Lemaire in 1867, and as M. warneri by George Nicholson in 1886, Arthur Henfrey reduced it to a variety of Miltonia spectabilis in 1851, and as such it was considered until 2002, when Cássio van den Berg reestablished it as a distinct species. The last Miltonia species to be discovered was M. kayasimae, found by an orchid collector not far from the city of São Paulo, in an area around nine hundred meters of altitude nearby the top of Serra do Mar mountains. It was named after their collector by Guido Pabst in 1976. So far very few plants were found, all living at the same area.
Since the genus Miltonia was established, many species, now classified under a number other genera, were submitted to it. The most noticeable cases were four of the five species of Miltoniopsis, a genus proposed in 1889 but only really accepted in 1976. Despite its somewhat similar flowers, Miltoniopsis are from cooler forests on the Andean slopes closely related to Cyrtochilum and only remotely related to Miltonia. Also five of the six Miltonioides species were occasionally considered as Miltonia until 1983 when Brieger and Lückel proposed this genus for them. These are species of more delicate and narrower flowers, from Mexico and Central America, which some taxonomists claim might be better classified under the genus Oncidium to whom they are closely related. The last common species which was occasionally classified under Miltonia is Chamaeleorchis warszewiczii, which is related to Oncidium and some taxonomists identify as Oncidium fuscatum.
In 1983, Brieger and Lueckel, considering that four species of Miltonia, M. candida, M. cuneata, M. kayasimae and M. russelliana, show the junction of the labellum with the column in a different angle than the other species, proposed the genus Anneliesia for them. Although this four species form a small sister clade to the rest of Miltonia species, the difference did not seem important enough to justify the acceptance of this new genus, therefore this proposal has not been generally accepted by the scientific community.
In 2001, based on molecular analysis, Norris Williams and Mark Chase, transferred a species previously classified under the genus Oncidium, as O. phymatochilum, to Miltonia. As this species shows a morphology that closer to Oncidium species than to Miltonia, because of its small yellowish flowers and highly branched inflorescence, this result and following transfer was a great surprise to most taxonomists. In 2005, Eric Christenson suggested a new genus and the name Phymatochilum brasiliense for it. There is no consensus about the name to be generally accepted as yet.
Molecular analysis show that Miltonia most closely related genus is Phymatochilum and then Aspasia, Brassia and Ada, which are the most important genera included in this that is one of the eight clades that form the subtribus Oncidiinae of tribus Cymbidieae.
The genus is named after Lord Fitzwilliam Milton, an English orchid enthusiast.
- Miltonia candida - Snow-white Miltonia
- Miltonia clowesii - Clowes' Miltonia
- Miltonia cuneata - Wedge-shaped Miltonia
- Miltonia flava - Yellow Miltonia
- Miltonia flavescens - Yellowish Miltonnia
- Miltonia kayasimae - Kayasima's Miltonia
- Miltonia moreliana - Morel's Miltonia
- Miltonia phymatochila
- Miltonia regnellii - Regnell's Miltonia
- Miltonia regnellii f. alba
- Miltonia regnellii f. citrina
- Miltonia regnellii f. travassosiana
- Miltonia regnellii f. veitchiana
- Miltonia russelliana - Russell's Miltonia
- Miltonia spectabilis - Outstanding Miltonia