Orchids can be quite flamboyant, sensual or downright sexy — some more so than others. The name orchid literally means testicle in Greek (ὄρχις/órkhis), a rather suggestive but suitable name it would seem. Linnaeus categorized the family as Orchidaceae, but the common name “orchid” came about later when John Lindley (incorrectly) aimed to extract the Latin stem (orchis) from Orchidaceae in 1845.
History & taxonomy
There are over 25,000 species of orchids in the world, some say as many as 30,000 and several hundred new species are discovered each year. There is evidence of orchids dating back as far as the age of the dinosaurs, 120 million years ago, making them not only the second largest but also the oldest flowering plant family in the world. Orchids are found on every continent except Antarctica (but is found on Macquarie Island, very close to Antarctica) and grow pretty much everywhere except for in the driest deserts and on glaciers. A majority of orchids are found in the tropics, mostly in Asia and South- and Central America. On top of this staggering number of natural species there are about 120,000 registered manmade hybrids, and more are registered all the time. Orchids are primarily grown for their beautiful flowers, with one exception. The seed pods from the Vanilla orchid (yes, vanilla is an orchid) are harvested as a spice, and vanilla is the second most expensive spice in the world after saffron.
The taxonomy changes all the time as science evolves, but the family Orchidaceae is currently placed in the order Asparagales with five recognised subfamilies. They are: Apostasioideae (2 genera, 16 species) from south-western Asia, Cypripedioideae (5 genera, 130 species) from the temperate regions as well as tropical America and tropical Asia, Vanilloideae (15 genera, 180 species) from humid tropical and subtropical regions as well as eastern North America, Epidendroideae (500+ genera, 20,000+ species) cosmopolitan*, Orchidoideae (208 genera, 3,630 species) also cosmopolitan*. (*Found more or less all over the world.)
Many orchids have a unique relationship with a single type of bird or insect that can pollinate their flowers. Charles Darwin reasoned that the orchid family was exceptionally adept at the mechanism of natural selection. For example, he argued that pollinator for the Angraecum sesquipedale orchid must have a tongue or proboscis long enough to reach from the mouth of the 30 centimeter long spur to the apex where the nectar was held. Scientists of the day laughed at this ridiculous notion, but a sphinx moth (Xanthopan morgani praedicta) equipped with a tongue of the appropriate length was actually discovered on Madagascar in 1903. Many of Darwin’s observations regarding orchid pollination can withstand critical scrutiny even today – almost a century and a half later.
How orchids grow
There are five basic types of orchids based on their growing conditions: Aquatics (grow in water), Epiphytes (grow on branches/mossy trees but are not parasitic), Lithophytes (grow among rocks/on stones), Saprophytes (grow in leaf litter) and Terrestrial (grow in sand/clay/soil). Most orchids are perennial epiphytes however and grow attached to trees or shrubs in the tropics and subtropics. The placement provides nice filtered sunlight, even moisture during the rainy periods, and constant air circulation.
Orchids has two growth patterns, monopodial and sympodial. Monopodial orchids grow one stem from a single bud. Leaves grow from the apex and the stem and grow longer accordingly. Once the monopodial orchid flowers from the centre top leaves, it has reached its maturity and will not grow any more. Sympodial orchids grow laterally rather than vertically, producing a series of adjacent shoots. The mature shoot will bloom and then stop growing and is later replaced. The growth continues by development of new leads along the rhizome, a creeping rootstock that is usually found underground.
Many orchids have pseudobulbs that can store water and nutrients for drier periods. Some species have big fat bulbs, others are narrow and tall. The whole base of the stem of sympodial epiphytes actually serves as a pseudobulb. Older pseudobulbs often shed their leaves and become dormant, called backbulbs. Other active pseudobulbs exploit the last reserves accumulated in these backbulbs until they eventually die off. In warm and humid climates, pseudobulbs are not necessary. Epiphytic orchids have modified aerial roots surrounded by a spongy epidermis called a velamen. The velamen is really good at absorbing humidity in the air. When the velamen fill with water it changes color from silver to a healthy green. The same thing happen when we water.
Orchids are distinguished from other plants by some very evident apomorphies, such as they are bilaterally symmetric (zygomorphic), many resupinate, one petal (labellum) is always highly modified, stamens and carpels are fused, and the seeds are extremely small.
Let’s take a quick dip into the nomenclature pool… It’s always good to know at least the basics, it actually makes it easier to know what you are looking at when you read about orchids. For example, if you see the name of an orchid where the species name is written in lowercase you know it is a pure species. Although, many people are pretty sloppy about this (even people who sell orchids), which makes it a bit harder. I am guilty of a level of sloppiness myself when I blog, but I do at least endeavor to capitalize correctly.
|Family||A taxonomic rank used for evolutionary, palaeontological and generic studies because they are more stable than lower taxonomic levels such as genera and species. Orchids belong to the Orchidaceae family.|
|Subfamily||Families are further divided into sub families based on the ancestral relations between organisms. The five sub families under Orchidaceae are: Apostasioideae, Cypripedioideae, Epidendroideae, Orchidoideae and Vanilloideae.|
|Alliance||A group of similar genera. For example the Cattleya Alliance, which include the following genera: Brassavola, ×Brassocattleya, Broughtonia, Cattleya, Encyclia, Guarianthe, Laelia, Myrmecophila, Sophronitis.|
|Genus||A group of related species (genetically similar plants), both naturally occurring families and hybrids. Names are capitalized and written in italics or underscored (plural = genera). For example: Cattleya, or Ascocenda (where Ascocenda is a cross between Ascocentrum x Vanda).|
|Subgenus||A taxonomic category ranking between a genus and a species. A subgeneric name can (but it is not customary) be used independently or included in a species name, in parentheses, placed between the generic and specific name. For example: Paphiopedilum (Parvisepalum) delenatii. Where Paphiopedilum delenatii belongs to the subgenus Parvisepalum.|
|Species||The second term in a name of orchids that occur naturally in the wild. It is a genetically unique plant with a lineage that can be traced back to one common ancestor. The species name is written in lower case and in italics. For example: falcata in the name Neofinetia falcata.|
|Subspecies||A subspecies has definable differences from the species and is more distinct than a variety but with enough genetic similarity that it will not be classed as a new species. It seems that subspecies is mainly used when variety and form do not provide enough distinction. Subspecies are limited to a distinct geographical area which is often reflected in the name. Abbreviated subsp. or ssp.|
|Variation||A variation (var.) epithet distinguishes between the typical appearance of the species and a variation within the species. A variation have significant horticultural differences from the typical species, such as growth habitat or size for example, and is only found is a fraction of the general population. Variations are not limited to a distinct geographical area. Just as a species is a more distinct description than a genus, a variety is a more distinct description than a form. For example Cattleya walkeriana f. alba is a white (or white and green) version of the species. The epithet (alba) is italicized but “var.” of “f.” is not .|
|Form||A form (f.) epithet distinguishes between the typical appearance of the species and sporadically occurring mutations that can sometimes be found within the broad population of the species. A form is often used to denote color variations (the alba form for example). For example Euanthe sanderiana f. alba is a white (or white and green) version of the species. The epithet (alba) is italicized but the abbreviation “f.” for form is not. It is pronounced “the alba form of Euanthe sanderiana.” (For some reason Kew has decided not to recognize these var./form definitions as accepted names, but it is still widely used among growers as the attributes are definite selling points and as a buyer I would definitely like to know what form I am actually getting…)|
|Hybrid||Man made crosses. Hybrid names are capitalized and not italicized. For example: Masdevallia Aquarius is a registered cross between Masdevallia urosalpinx x Masdevallia davisii. The creator can name the hybrid he creates when registering the cross. If the hybrid is unregistered, the parents are written in parentheses listing the seed parent first then the pollen parent separated with an x. For example: Paphiopedilum (haynaldianum x sanderianum). Different color forms are not spelled out when it comes to hybrids, but growers often put the color in parentheses behind the name to indicate what they are actually selling. For example: Ascocenda Princess Mikasa (blue).|
|Natural hybrid||These crosses occur naturally in the wild. Indicated by an “x” before the species name and written in lower case and in italics. For example, Masdevallia × alvaroi – a natural hybrid between Masdevallia amanda and Masdevallia picturata.|
|Primary hybrid||Crosses between two pure species. Hybrid names are capitalized and not italicized. For example: Paphiopedilum Dellaina is a registered primary hybrid between Paphiopedilum delenatii x Paphiopedilum chamberlainianum.|
|Intergeneric hybrid||Hybrids between different genera. Names are capitalized and written in italics or underscored. Some have even been given new names, for example, Odontonia (Miltonia x Odontoglossum).|
|Grex||From the Latin noun grex (= flock) is used to expand the Linnean binomial system to include horticultural hybrids. It is a registered hybrid’s identity. It is capitalized and not italicized. For example: Phalaenopsis Mini Mark, a cross between Phalaenopsis Micro Nova (P. maculata x P. parishii) and P. philippinense.|
|Cultivar ⁄ Clone||Identifies a single unique plant and all of its divisions or propagations, including mericlones since a close is an exact remake of the genetic code of the source. The cultivar or clonal name is capitalized, not italicized and always found in single quotes. For example: Phalaenopsis Mini Mark ‘Holm’, or Ascocentrum miniatum ‘Kai-Gold’.|