Plants of Current Interest: January
Supplied by Christopher Weddell, Information and Interpretation Technician @ Wisley.
Most of the images were supplied by the book publishers Dorling Kindersley.
Welcome to Wisley during mid-winter. With the 'Orchids for All' display in the Glasshouses starting in mid-January, this month orchids are being highlighted.
Orchids make up one of the largest families of flowering plants with around 30,000 species in the wild. They occur on every continent except Antarctica, with the greatest number being found in tropical and subtropical areas. Many species also grow in temperate and alpine regions, including the UK. Britain has 26 species of terrestrial orchids, some of which are extremely rare and unusual.
Despite the great number of wild species commercial growers and enthusiasts are always introducing new orchid hybrids. Since the first flowering of a hybrid in 1856 over 100,000 recognisable orchid hybrids have been bred.
Today, tropical and subtropical orchids are grown commercially for cut flowers but traditionally the orchids used by man are Vanilla planifolia, for its aromatic seedpod used to flavour food, and Orchis for its starchy roots, which when dried are used as an ingredient in Turkish delight.
Orchid Flowers
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However different orchid flowers look they all follow the same basic pattern. Uniquely, orchids produce a central column with contains both the male and female parts, with the pollen hidden by a protective anther cap. Surrounding the column are three outer sepals and three inner petals, with the sepals mostly resembling the petals. One petal, called the lip, is always distinct, either brightly coloured, a different size or of a different shape. |
Pseudobulbs
Many epiphytic orchids produce pseudobulbs, swollen stems joined by a rhizome, which are essentially used for water storage.
Orchid Habitats
In their natural environment orchids can be divided by growth habit into two groups, epiphytes (including lithophytes) and terrestrials. Those in cultivation are mostly epiphytic.
Epiphytes are plants that grow on other plants but are not parasitic on them. Lithophytes are plants that grow on rock or stone and terrestrials are plants that grow in the soil.
Most tropical and sub-tropical orchids are epiphytes, and a few are lithophytes. They obtain all the nutrients and water they need from moisture in the air as well as from rain and tropical mists. In colder regions, where exposed roots would not survive, orchids grow more conventionally in the ground as terrestrials.
Cymbidium
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Originating in temperate and tropical parts of China, Japan, south-east Asia and Australia, cymbidiums are probably the most widely cultivated of all orchids because of their ease of cultivation and long-lasting flowers. Thousands of hybrids have been bred, with flowers ranging in colour from white, yellow and orange to pink, red, brown and green, and varying in size from a standard 10-15cm (4-6in) to a miniature 5cm (2in) across.
Cymbidium Banff |
Dendrobium
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The second largest genus of orchids. Most Dendrobium species are epiphytic and come from subtropical and warm regions of south-east Asia, Australia and New Zealand.
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Flowering from winter to spring, the larger Dendrobium hybrids can produce flower spikes 90-120cm (3-4ft) in height, although many produce spikes half that height and some have solitary blooms.
Dendrobiums fall into two groups, those that require a lot of heat to grow well and those that thrive in cooler conditions. Of the latter, hybrids of Dendrobium nobile make excellent houseplants for cool rooms. Dendrobium cunninghamii from New Zealand is the hardiest species, thriving under glass in barely frost-free, airy conditions.
Phalaenopsis
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This large genus is noted for its beautiful and extremely long-lasting flowers. The spikes of flowers may be upright or arching, carrying from one or two to 50 or 60 blooms on a single metre-long spike.
Many thousands of hybrids have been produced, with flower colours including white and almost every other colour except blue.
Phalaenopsis (Paifang's Queen x Salu Spot) x Phalaenopsis Baby Angel |
Miltonia
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This is a small genus of epiphytic or lithophytic orchids from Central and South America, found in mountainous regions from 300 to over 2,000 metres. |
They are commonly known as pansy orchids, due to the shape of the showy, fat-lipped, fragrant flowers, produced in racemes from the base of the pseudobulbs. There are many colourful hybrids, often blooming twice a year, with up to six flowers on a spike.
Miltonias make good houseplants if given a shaded, humid environment and a little heat in winter.
Miltonia Anjou 'St Patrick'
Laelia
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There are about 50 species of Laelia, coming mostly from central and northern South America. Laelia gouldiana, a cooler growing species, has long-lasting large pinkish-purple flowers and is popular with beginners due to its relative ease of cultivation.
Laelia purpurata, commonly called the queen of laelias, is the national flower of Brazil and has given rise to more cultivated varieties than any other orchid.
Laelia anceps |
Oncidium
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This group of orchids originates in tropical and temperate areas of Central and South America. Most Oncidium species in cultivation are evergreen and epiphytic, their small yellow flowers with dark, red-brown markings are produced in airy sprays. Oncidium ornithorhynchum (pictured) however, has pink, heliotrope-scented flowers. |
Odontoglossum
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This is a large genus of epiphytic or lithophytic, evergreen orchids originating in high altitude areas of Central and South America. Because of their mountainous origins, nearly all the species and hybrids do well in cool conditions.
The flower spikes are very variable, with the flowers exhibiting almost every colour imaginable in addition to being marked in a great range of patterns.
Odontoglossum crispum |
Masdevallia
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Native to tropical America, species of Masdevallia occur from warm lowlands to high altitudes, though most are found at high elevations in cloud forests.
Unlike many orchid flowers, those of masdevallias are not obviously divided into petals and sepals. The sepals are joined to form a triangle while the petals are much reduced. The colours vary from white, pink and red to yellow, orange and brown, with some having contrasting venation which makes them appear to have stripes.
Masdevallias lack pseudobulbs and grow from a root system that produces short stems, with a single fleshy leaf.
Masdevallia Angel Frost |
Click here if you want to know more about growing orchids.
The Orchid Review is the leading publication on this group of fascinating plants.
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