The medial petal, called the labellum or lip (6), which is always modified and enlarged, is actually the upper medial petal; however, as the flower develops, the inferior ovary (7) or the pedicel usually rotates 180°, so that the labellum arrives at the lower part of the flower, thus becoming suitable to form a platform for pollinators. This characteristic, called resupination, occurs primitively in the family and is considered apomorphic, a derived characteristic all Orchidaceae share. The torsion of the ovary is very evident from the longitudinal section shown (below right). Some orchids have secondarily lost this resupination, e.g. Epidendrum secundum.
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.
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.
The amount of drainage your pot has will depend on the size of the pot, with larger pots requiring more drainage holes than smaller pots. Since orchids prefer to grow in smaller pots, a good rule of thumb is to make sure the pot has 4-8 holes if it’s 4 inches (10 centimeters) or so, while larger orchid pots (around 6 inches or 15 centimeters) should have 8-12 holes for drainage.
Also called the Butterfly orchid, this flower comes in striking colors such as burgundy and bright gold, and it can even have foliage that is green and speckled. It blooms for several months, needs only moderate light conditions, and it is very easy to grow and maintain. It is a truly stunning plant that can complement your garden regardless of what else is planted there.
The seeds are generally almost microscopic and very numerous, in some species over a million per capsule. After ripening, they blow off like dust particles or spores. They lack endosperm and must enter symbiotic relationships with various mycorrhizal basidiomyceteous fungi that provide them the necessary nutrients to germinate, so all orchid species are mycoheterotrophic during germination and reliant upon fungi to complete their lifecycles.

The characteristic that makes these different than many other orchids is their shape, which is triangular, blocky and compact, or thin, whiskery, and elongated. They bloom in the summer and require certain temperatures and humidity levels, so you should research them before you decide to purchase them. They can be tricky to grow and therefore, they are better for people who are more experienced in the garden, and they come in colors such as yellow-orange and have leaves that are a beautiful shade of green.

The Epidendroideae subfamily is the most widespread subfamily. It represents more than eighty percent of orchid species, and includes over 10,000 types of orchids. Although members of the Epidendroideae subfamily are present in temperate regions, they are most prevalent in the tropics of the Eastern and Western hemispheres. There orchids typically have single anthers with sub-erect structures.
^ Guillaume Chomicki; Luc P.R. Bidel; Feng Ming; Mario Coiro; Xuan Zhang; Yaofeng Wang; Yves Baissac; Christian Jay-Allemand & Susanne S. Renner (2015). "The velamen protects photosynthetic orchid roots against UV‐B damage, and a large dated phylogeny implies multiple gains and losses of this function during the Cenozoic". New Phytologist. 205 (3): 1330–1341. doi:10.1111/nph.13106.
Also called Cockleshell orchids, they have no fragrance, but they do bloom for several consecutive months, making them appealing for people who want color in their garden for long periods of time. The Encyclia orchid has dangling petals and sepals, which is why some people say it resembles an octopus. It thrives when planted on an orchid mount because this simulates the epiphytic growing conditions found in the wild, and it comes in colors such as yellow-white with purple throats at the top.
Speaking of cut Cymbidium flowers, my friend has several outdoor Cymbidium and the once-a-year flowering always brought her lots of joy and pride. It’s like an annual EXPLOSION of flowers that fills her whole back yard! Right before the prom, their teenage neighbor forgot to get his date some flowers, and for some reason, he thought it was okay to make a bouquet out of these Cymbidium flowers without any permission. She was so upset about the loss that the thoughtless boy had to make up the mistake by working in her garden for the rest of the year. The moral of the story? If you decide to steal someone’s orchids, you’d better not get caught! Learn more about Cymbidium orchids.
Phalaenopsis – Phalaenopsis, otherwise known as the moth orchid, this is perhaps the most common of various orchid flowers you can buy in a general garden center. Moth orchids bloom once or twice a year, and each flower can last as long as three months with the proper care, and are the longest-lasting of orchid blooms. Moth orchids do well with warm temperatures in the house, in the upper 70’s on average.
^ 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.
Most orchids are not heavy feeders. Many orchids bloom year after year with no fertilizer at all. During active growth, when new leaves are being produced, you may fertilize every other time you water at half the strength recommended on the fertilizer package. However, it's important to deliver water without fertilizer at least once a month to flush excess fertilizer salts from the bark mix and avoid fertilizer burn to the roots.

Using the molecular clock method, it was possible to determine the age of the major branches of the orchid family. This also confirmed that the subfamily Vanilloideae is a branch at the basal dichotomy of the monandrous orchids, and must have evolved very early in the evolution of the family. Since this subfamily occurs worldwide in tropical and subtropical regions, from tropical America to tropical Asia, New Guinea and West Africa, and the continents began to split about 100 million years ago, significant biotic exchange must have occurred after this split (since the age of Vanilla is estimated at 60 to 70 million years).
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 Bulbophyllum orchid genus is the largest in the Orchidaceae family, with over 1800 species, making it the third largest genus of plants. (Taxonomists will probably eventually split it into several smaller genera, but with so many types of orchids it's a massive undertaking!) They differ widely in appearance, but all have a single leaf emerging from the top of the pseudobulb, flower stems coming from the bottom of the pseudobulb, and a hinged lip designed to tip insects against the column. Many are pollinated by flies, and stink like dung or rotting carcasses, which is a great conversation starter and gives you bragging rights for putting up with it! (They don't all stink, fortunately.) The rhizomes wander all over the place and often branch freely, so it's easy to grow an impressive specimen.