Family Profile: The Orchidaceae

By Kellie Glover & Virginia Iwinski

Figure 1. Cyrtopodium punctatum, the cigar
orchid, is an endangered species which is
native to Florida. Photo credit: Al Menk.

This post is one of a series from professor Nisse Goldberg's Plant Taxonomy students at Jacksonville University. FNPS blogger Laurie Sheldon assisted the students with their initial drafts, providing suggestions for editing and content development.

Classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Orchidales
Family: Orchidaceae


Figure 2. Orchid leaf with obvious parallel
veins. Photo credit: Fastily.
Characteristics
Leaf: alternate, spiral or 2-ranked, simple, and are often plicate, basal, or along the stem
Flower: bisexual, bilateral with tepals forming a lip or labellum
Fruit: capsule

Description
The orchid family, Orchidaceae, is one of the largest flowering plant families in the world.   It is so large that there are actually more orchid species than twice the number of bird species! In Florida, we are lucky to have so many 109 native species, varieties, and hybrids. Unfortunately, 56 of those species are listed as endangered in Florida. The state also has 13 non-native species.

This family is most commonly found in tropical regions. However, given the large number of species in this family, it is not surprising that they are found growing in a variety of habitats. Some are found in semideserts, and others are pantropical which means they are only found in specific regions or certain countries. There are even species that bloom within the Arctic Circle! Orchids can be terrestrial, found growing on other plants (epiphytic) or rocks (lithophytic). Epiphytic plants differ from parasitic species like mistle toe in that they do not harm their host.
Figure 3. Note the labellum of Encyclia
tampensis
, a native Florida orchid.
Photo credit: Shirley Denton

Some of the most recognizable features among orchids are the parallel veins in their leaves (Fig. 2) and the labellum or lip (Fig. 3) component of their flowers. The flowers are usually resupinate, which means they were twisted 180° during development.

The family Orchidaceae includes plants that are economically important. For example, Vanilla planifolia is the source of vanilla extract, a product used in kitchens around the world. Vanilla extract comes from the orchid’s fruit or capsule.  The family also includes popular ornamentals Cattleya, Dendrobium, Epidendrum, Paphiopedilum, Phalaenopsis, Vanda, and Oncidium.

Figure 4. Ophrys insectifera, the fly orchid
The orchid flowers attract both specialist and generalist insect pollinators, including  butterflies, bees, and flies. Some even attract birds and others can self-pollinate. There are many fascinating methods that the orchids attract pollinators.  One method known as pseudocopulation occurs in flowers where the labellum resembles a female insect at rest.  Male insects are attracted to the ‘female’ and as they search for their mate, pollinia or pollen sacs  stick to the insect.  The insect may then deposit the pollinia on the stigma of another flower, while it still searches for the ‘female’.  There are also Orchid species that resemble flies (Fig. 4) or bees that even have the same colored hair tufts. Some of these species release pheromones like those of the female insect that their appearance mimics in order to attract the males!


References
Judd, WS, Campbell, SC, Kellogg, EA, Stevens, PF, and Donoghue, ML. 2008. Plant systematics: A phylogenetic approach. Sinauer Associates, Inc. Massachusetts, USA.
http://www.florida.plantatlas.usf.edu/
http://www.orchids.co.in/plant-facts/orchid-pollination.shtm
http://blog.hmns.org/?tag=darwins-orchid
http://victicase.wordpress.com/2010/04/04/orchids-description/
http://www.botany.com/orchidaceae.html


Image Sources
Figure 1. http://florida.plantatlas.usf.edu/Photo.aspx?id=12689
Figure 2. http://en.wikipedia.org/wiki/File:Orchidaceaeleaf3500ppx.JPG
Figure 3. http://www.shirleydenton.com/plants/web_pics/e/encycl_tam_fl07.jpg
Figure 4. http://static.panoramio.com/photos/original/23492298.jpg

Comments

One really good resource for Florida Native Orchids is the Florida Native Orchids website, with lots of information on our native orchids, including plant profiles, distribution information, and a lot of photographs taken in the field.

The Florida Native Orchids Website

There are a few corrections/additions I would like to make to add some minor corrections, as well as make this post more relevant to Florida's orchids:

1. Some orchid leaves do not have obviously parallel veins, such as our native species of Listera and Goodyera. Goodyera leaves actually have a network of veins colored in white, giving the leaves a scaled appearance.

2. An orchid flower oriented with the lip downward is resupinate, regardless of the twist in the ovary/pedicel to orient it this way--usually, it does involve a 180 degree twist, but in the event of a pendent or angled flowering stem, a lesser twist (or no twist at all) may be required to orient the lip downward. Orchid flowers are positively geotropic when this happens. Conversely, an orchid flower with the lip uppermost is non-resupinate. One interesting example of a non-resupinate orchid is Florida's own Malaxis spicata, whose pedicel undergoes a 360 degree twist to present the flowers in a non-resupinate fashion.

3. When mentioning commercial Vanilla, it should be noted that Florida is host to four species of Vanilla. Our native V. phaeantha can be used to make vanilla flavoring, but it is considered inferior to the commercial species.

4. We have a genus of interesting tricksters - the Calopogons - which use rank deception to lure pollinators to their flowers just like the bee orchids. You can read more about that mechanism here:

Calopogon tuberosus page

Good to know. Thanks, Prem!
You are a wealth of information,Prem. We appreciate your commentary!
Rufino Osorio said…
Professor Goldberg's students should bear in mind that "aceae" is a Latin plural suffix. Thus, the names of plant families ending in "aceae" are already plural. The titles to the homework assignments of Professor Goldberg's students should thus read: "The __________aceae" (fill in the blank with the plant family root word). Adding an "s" to a botanical family name ending in "aceae" is equivalent to writing "mices" or "geeses." "Mice" and "geese" are already plural so the "s" at the end is unnecessary.
Thanks for the tip; it was my error, and a typo at that.

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