To give you a better feel for how orchid subfamilies, tribes, and genera are interconnected, we created a compendium of popular American orchids. It plots over 100 “local” genera of orchids so you can see just how impressive and expansive this family is. You may be surprised that some of these vibrant, exotic looking orchids exist in your own backyard!  Want to learn more about flowers and plants? Check out our other compendiums featuring types of roses and types of desert plants.

^ Zhang, Guo-Qiang; Liu, Ke-Wei; Li, Zhen; Lohaus, Rolf; Hsiao, Yu-Yun; Niu, Shan-Ce; Wang, Jie-Yu; Lin, Yao-Cheng; Xu, Qing; Chen, Li-Jun; Yoshida, Kouki; Fujiwara, Sumire; Wang, Zhi-Wen; Zhang, Yong-Qiang; Mitsuda, Nobutaka; Wang, Meina; Liu, Guo-Hui; Pecoraro, Lorenzo; Huang, Hui-Xia; Xiao, Xin-Ju; Lin, Min; Wu, Xin-Yi; Wu, Wan-Lin; Chen, You-Yi; Chang, Song-Bin; Sakamoto, Shingo; Ohme-Takagi, Masaru; Yagi, Masafumi; Zeng, Si-Jin; et al. (2017). "The Apostasia genome and the evolution of orchids" (PDF). Nature. 549 (7672): 379–383. doi:10.1038/nature23897. PMID 28902843.
With the different orchid types, it’s important to master the watering schedule. If orchids have pseudobulbs, enlarged stem structures that store water, the orchid potting mix can dry out a little between waterings. Orchid species that are epiphytes and grow on tree branches in tropical rainforests are adapted to receiving water from daily rain, so they need more frequent watering.  
The term "botanical orchid" loosely denotes those small-flowered, tropical orchids belonging to several genera that do not fit into the "florist" orchid category. A few of these genera contain enormous numbers of species. Some, such as Pleurothallis and Bulbophyllum, contain approximately 1700 and 2000 species, respectively, and are often extremely vegetatively diverse. The primary use of the term is among orchid hobbyists wishing to describe unusual species they grow, though it is also used to distinguish naturally occurring orchid species from horticulturally created hybrids.
The family encompasses about 6–11% of all seed plants.[4] The largest genera are Bulbophyllum (2,000 species), Epidendrum (1,500 species), Dendrobium (1,400 species) and Pleurothallis (1,000 species). It also includes Vanilla–the genus of the vanilla plant, the type genus Orchis, and many commonly cultivated plants such as Phalaenopsis and Cattleya. Moreover, since the introduction of tropical species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids and cultivars.
Because these orchids are top-heavy with lots of blooms on each stem, this type of orchid often requires staking. There are over 1,000 species in this category, and they usually come in colors such as white, lavender, or yellow. One of its biggest advantages is the fact that it can grow almost anywhere, regardless of the zone you live in, and some of them keep their leaves all year long. They can also come in more than one color per bloom, which makes them especially attractive.

The orchid plant is also unique in its morphology (form or structure). We can begin with the leaves and work our way down to the roots. The leaves of many orchids in cultivation are unique in that they are specifically designed for water conservation (as is true for almost every orchid structure). They have a heavy waxy leaf coating and specialized stomata (openings through which the leaf “breathes”) that help to prevent water loss during transpiration (the act of the plant “breathing”). Many orchids utilize CAM photosynthesis as well, which in essence means that the plants collect materials during the day and then process them at night.


The potting mixture, or growing medium, for a phalaenopsis orchid should be good at both absorbing water and providing airflow to the roots of the plant. Therefore, consider using media such as tree bark, coconut coir, clay pellets, perlite, pumice pebbles, and sphagnum moss, either on their own or blended together. If you live in a humid climate, choose a courser potting mixture that dries quickly and provides the best drainage. On the other hand, those who live in a dry climate should use a finer medium that will dry more slowly and hold more moisture.
Orchids are an incredibly unique and fascinating group of plants. Many people can identify a Phalaenopsis (moth orchid) or Cattleya (the old corsage orchids), but the question often is asked, “What makes an orchid an orchid?” Orchids have some morphological (physical) traits that make them stand out from other plant families. In orchids, many of their floral parts come in groups of three. There are three sepals, which are the outer petals; these are what you see when you look at an unopened bud. There are also three petals, but in orchids one of the petals has been specialized into a labellum, or lip. This is usually the bottommost petal, and it helps to attract the pollinator to the reproductive organ. In orchids the reproductive organ, known as the column, combines both the male and female parts in one structure.
Like most monocots, orchids generally have simple leaves with parallel veins, although some Vanilloideae have reticulate venation. Leaves may be ovate, lanceolate, or orbiculate, and very variable in size on the individual plant. Their characteristics are often diagnostic. They are normally alternate on the stem, often folded lengthwise along the centre ("plicate"), and have no stipules. Orchid leaves often have siliceous bodies called stegmata in the vascular bundle sheaths (not present in the Orchidoideae) and are fibrous.
Like most monocots, orchids generally have simple leaves with parallel veins, although some Vanilloideae have reticulate venation. Leaves may be ovate, lanceolate, or orbiculate, and very variable in size on the individual plant. Their characteristics are often diagnostic. They are normally alternate on the stem, often folded lengthwise along the centre ("plicate"), and have no stipules. Orchid leaves often have siliceous bodies called stegmata in the vascular bundle sheaths (not present in the Orchidoideae) and are fibrous.
Catasetum orchids, along with the other members of the Catasetum alliance, have big, thick pseudobulbs with an attractive fan of thin leaves along their length. The flowers can be very showy, but are unisexual, so that male and female flowers look different. Lighting affects which kind appears. They need a dry rest after flowering when the leaves drop.
Cycnoches orchids have unisexual flowers, meaning they have separate male and female flowers which look different (usually just one of the two types of orchid flowers each time it blooms). The flowers are usually make a very dramatic display. After flowering, the leaves drop off and it enters a dry rest; don't water until it starts to grow again or it will rot.

The vast majority of orchids grown in the home are epiphytes, meaning they live in nature by clinging to trees or even stones. The roots of these plants are highly specialized organs that differ dramatically from normal plant roots. Of course, it's hard to generalize about anything when it comes to orchids. This is the single largest group of plants in the world, so for every rule, there are 100 exceptions.
If your Catasetum orchid leaves begin to yellow and drop off, do not despair; this deciduous orchid loses its leaves naturally during winter dormancy. There is much variation in appearance between Catasetum species, but one feature they all have in common is the trait of producing male or female flowers, which bear little resemblance to each other. The male flowers have an anatomical trigger that forcefully ejects pollen onto visiting bees.

The Orchideae tribe is the largest tribe within the Orchidoideae subfamily, and contains a variety of flower forms. Flowers in this tribe dominate the orchid flora in the temperate Northern Hemisphere, though they can also be found in East Asia. These orchids usually have a three-lobed lip without a basal spur, prominent caudicles, and erect anthers.
A study in the scientific journal Nature has hypothesised that the origin of orchids goes back much longer than originally expected.[14] An extinct species of stingless bee, Proplebeia dominicana, was found trapped in Miocene amber from about 15-20 million years ago. The bee was carrying pollen of a previously unknown orchid taxon, Meliorchis caribea, on its wings. This find is the first evidence of fossilised orchids to date[14] and shows insects were active pollinators of orchids then. This extinct orchid, M. caribea, has been placed within the extant tribe Cranichideae, subtribe Goodyerinae (subfamily Orchidoideae). An even older orchid species, Succinanthera baltica, was described from the Eocene Baltic amber by Poinar & Rasmussen (2017).[15]
The quality of water used, whether for spraying or watering, is of great importance. Since tap water has often been chemically treated, generally with chlorine, it should be used with caution. The best water for orchids is undoubtedly rainwater. Rainwater, as it passes through the air, dissolves and absorbs many substances such as dust, pollen and other organic matter. This enriched rainwater contributes to the nourishment of the plant.
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