Nutrients for epiphytic orchids mainly come from mineral dust, organic detritus, animal droppings and other substances collecting among on their supporting surfaces. The cells of the root epidermis grow at a right angle to the axis of the root to allow them to get a firm grasp on their support. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes. It is made of dead cells and can have a silvery-grey, white or brown appearance. In the older parts of the roots, a modified spongy epidermis, called a velamen, has the function of absorbing humidity. In warm and constantly humid climates, many terrestrial orchids do not need pseudobulbs.Įpiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. One is used as a food reserve for wintry periods, and provides for the development of the other one, from which visible growth develops. Some sympodial terrestrial orchids, such as Orchis and Ophrys, have two subterranean tuberous roots. The root caps of terrestrial orchids are smooth and white. Terrestrial orchids may be rhizomatous or form corms or tubers. Neotinea lactea, collected in Sardinia the small size, compared to a one-Euro coin, and the two globose tuberoids typical of the Neotinea genus are highlighted Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil. While a new lead is developing, the rhizome may start its growth again from a so-called 'eye', an undeveloped bud, thereby branching. The growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. Sympodial orchids grow horizontally, rather than vertically, following the surface of their support.
Orchid album series#
The plant produces a series of adjacent shoots, which grow to a certain size, bloom and then stop growing and are replaced.
The stem of orchids with a monopodial growth can reach several metres in length, as in Vanda and Vanilla. Monopodial: The stem grows from a single bud, leaves are added from the apex each year, and the stem grows longer accordingly.Germinating seeds of the temperate orchid Anacamptis coriophoraĪll orchids are perennial herbs that lack any permanent woody structure. Moreover, since the introduction of tropical species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids and cultivars. It also includes Vanilla (the genus of the vanilla plant), the type genus Orchis, and many commonly cultivated plants such as Phalaenopsis and Cattleya. The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). The family encompasses about 6–11% of all species of seed plants. Regardless, the number of orchid species is nearly equal to the number of bony fishes, more than twice the number of bird species, and about four times the number of mammal species. The determination of which family is larger is still under debate, because verified data on the members of such enormous families are continually in flux. The Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. Orchids are plants that belong to the family Orchidaceae ( / ɔːr k ə ˈ d eɪ ʃ iː/ or-kə- DAY-shee ), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant.Īlong with the Asteraceae, they are one of the two largest families of flowering plants.