ARTICLE | Remarkable Orchids

We know orchids from florists and gardening supermarkets, but few people know how rich this group of plants really is. There is no right answer to how many orchids exist. Over 27,000 species are currently known to science, but dozens more are discovered every year.

Orchids inhabit not only tropical forests but almost the whole world. More than 60 species of orchids grow in Czechia. The world's northernmost orchids are found in Europe and Siberia. For example, Dactylorhiza lapponica and Lysiella oligantha grow in Scandinavia beyond 70̊ north latitude. The southernmost orchids in the world are Corybas dienemum and C. sulcatus, which grow on Macquarie Island (located south of New Zealand, about halfway between Tasmania and Antarctica).

In tropical mountains, orchids can be found in alpine vegetation and among rocks as rock plants at altitudes of over 4,000 metres above sea level. In the Ecuadorian Andes, orchids of the genus Myrosmodes grow at altitudes between 3,500 and 4,800 metres.

One of the largest orchids in the world is the Grammatophyllum speciosum from Southeast Asia. It grows epiphytically on the thick branches of mighty trees. The pseudobulbs of this orchid can grow up to a length of three metres, and the whole clump can weigh over a tonne. The flower stalks are also three metres long, with 30-50 flowers per stem, about 15 cm wide.

The tallest orchids are from the genus Sobralia, about five metres tall. However, the tallest so far has been S. altissima with a 13.4 m long stem. Vanilla orchids also have long stems, but they need support to climb on.

The North Vietnamese Paphiopedilum hangianum, discovered in 1999, has some of the largest flowers. Its massive flowers are up to 16 cm wide and have few rivals in terms of flower size. Notable is also P. sanderianum, whose petals are elongated at the tips and reach up to a metre in length. Orchids from other genera also have large flowers, e. g. plants from the genera Sobralia, Cattleya, Vanda or Angraecum.

Among the smallest orchids in the world are some species of the genus Bulbophyllum, with its pseudobulbs reaching only 3-4 mm.

Many orchids have tiny flowers around 1-2 mm. Some species have many, e.g., Fairy orchids (genus Oberonia) can have up to several thousand in one inflorescence. Other orchids may have single flowers, e. g. some species of the genera Lepanthes, Pleurothallis or Stelis.

Quite special are two species of the South Australian genus Rhizanthella, which grow and flower underground. They have no leaves, do not form chlorophyll and live in symbiosis with fungi.

Get to know the world of orchids in the Fata Morgana Greenhouse of the Prague Botanical Garden during the exhibition “Orchids - Treasures of the Vietnamese Jungle” which takes place from 3 to 19 March.