Some orchids, such as Neottia and Corallorhiza, lack chlorophyll, so are unable to photosynthesise. Instead, these species obtain energy and nutrients by parasitising soil fungi through the formation of orchid mycorrhizas. The fungi involved include those that form ectomycorrhizas with trees and other woody plants, parasites such as Armillaria, and saprotrophs. These orchids are known as myco-heterotrophs, but were formerly (incorrectly) described as saprophytes as it was believed they gained their nutrition by breaking down organic matter. While only a few species are achlorophyllous holoparasites, all orchids are myco-heterotrophic during germination and seedling growth, and even photosynthetic adult plants may continue to obtain carbon from their mycorrhizal fungi.
This tribe is fairly large and consists of four genera — Dendrochilum, Pholidota, Chelonistele, and Coelogyne — and over 300 species. They are native to the tropical and subtropical regions of the Old World. Coelogyne is the most popular genus. Its orchids are characterized by a three-lobed lip that is concave at the base, and a hooded or winged column.
The complex mechanisms that orchids have evolved to achieve cross-pollination were investigated by Charles Darwin and described in Fertilisation of Orchids (1862). Orchids have developed highly specialized pollination systems, thus the chances of being pollinated are often scarce, so orchid flowers usually remain receptive for very long periods, rendering unpollinated flowers long-lasting in cultivation. Most orchids deliver pollen in a single mass. Each time pollination succeeds, thousands of ovules can be fertilized.
Orchids of all types have also often been sought by collectors of both species and hybrids. Many hundreds of societies and clubs worldwide have been established. These can be small, local clubs, or larger, national organisations such as the American Orchid Society. Both serve to encourage cultivation and collection of orchids, but some go further by concentrating on conservation or research.
The most common type of orchid is probably the moth orchid, or the Phalaenopsis orchids. These are the plants that you can buy from a standard grocery store. Or if you happen to live close by an Asian supermarket, you will find truck-loads of the white or purplish-pink variety. Some fashion/interior designers even dubbed this purplish-pink color as “orchid.” (This is ultra confusing for an orchid grower, as orchids come in a million different shades and colors, but well, these are the same people who invented colors like sour lemon and spiced mustard. It’s just all marketing!)
About 30,000 species of orchids come from all over the world, on every continent except Antarctica. As you can imagine, they come from a wide range of habitats and each type of orchid has different care requirements. Their incredible diversity also means you can always find another interesting orchid type to grow, which is one of the principal reasons the orchid hobby is so addictive!
Masdevallia is one of my favorite types of orchids! They have triangular flowers (the petals are tiny, so you just see the three sepals.) They need cool temperatures to do well, and like a lot of humidity, but are otherwise quite easy to grow. (But they have a reputation as being hard to grow from people who've ignored their temperature and humidity requirements.)
With a shape that is similar to a dancing lady, the Oncidium orchid is low-maintenance and easy to grow, and it comes in stunning colors such as bright yellow and gold. The variety called Sharry Baby has a chocolate-like scent, and although simple to grow, the Oncidium orchid does require a lot of moisture and humidity to thrive. If you notice any type of deformities in the leaves of this plant, it is likely because this requirement has not been met. They are truly beautiful bloomers.
My favorite type of orchid is the lady slipper orchid because of their strange appearance. They are like no other types of flowers and have pouch-shaped lips. The mostly terrestrial and lithophytic slipper orchids include four genera—Paphiopedilum, Phragmipedium, Cypripedium and Selenipedium. But most Cypripedium and Selenipedium are not plants for the beginner because they can be quite difficult to grow under cultivation unless you live in temperate regions with Cypripedium growing wildly in your back yard!
Orchids have been used in traditional medicine in an effort to treat many diseases and ailments. They have been used as a source of herbal remedies in China since 2800 BC. Gastrodia elata is one of the three orchids listed in the earliest known Chinese Materia Medica (Shennon bencaojing) (c. 100 AD). Theophrastus mentions orchids in his Enquiry into Plants (372–286 BC).
The goal is to get each mix particle to absorb as much water as possible. To give the potting mix enough time to absorb water, place the entire pot in a bowl of water for 10 to 15 minutes, then lift it out and let the excess water drain before putting the pot back in place. This technique works well for orchids potted in clay. Since clay is porous, water penetrates the walls of the pot and is absorbed by the bark.
Orchid flowers are all bilaterally symmetrical with three petals and three sepals. Their seeds develop in capsules and are extremely tiny, sometimes mistaken for dust or spores. Because the seeds are so small, they don’t contain enough nutrition to grow a new plant themselves, so they develop a symbiotic relationship with fungus, which provides the nutrients for them to grow.
The Lycaste orchid genus, similarly to its relative Anguloa, likes intermediate-to-bright light, intermediate-to-cool temperatures, and high humidity. The flowers look rather different, though; they are more-or-less triangular in shape because the sepals point outward while the petals point forward. These orchids are very fun to grow, and will thrive if you get their care right.
Epidendrum orchids are among the oldest genera in the orchid taxonomy. Originally, this genus included all epiphytic orchids. As knowledge of the different types of orchids expanded, the classification became much more refined; for example, there are now some terrestrial species in the Epidendrum genus, and a great many other species have been moved to other genera. Still, over 1000 Epidendrum species exist. They are usually easy to grow, and most have tall canelike pseudobulbs that lean all over the place and frequently produce keikis. Fun orchids!
The den-phal type are warm growing year round and do, just by happenstance, bear flowers similar in appearance to the genus Phalaenopsis. They can be distinguished by plant habit (most Dendrobium have pseudobulbs that resemble tall canes) and flower shape. Den-phals have a spur at the back of the lip; some are more pronounced, others less. They are also borne on very strong upright to barely arching stems. Interesting to note, den-phals can rebloom on old canes.