Post on 19-Jun-2015
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ORCHIDACEAE
GROUP MEMBERS:MICHELLE BAILEYMARK BASTIANREHANA FAREEDSHEBIKI JEFFREYTHESIA KINGBHAVINA POORANKIMBERLY SANGSTER
ORCHID FAMILY (ORCHIDACEAE)Largest family of flowering plants
Terrestrial, epiphytic, or saprophytic herbs
Orchid flowers come in different colours except black
Example of an orchid is Vanilla planifolia, native to Mexico and Central America
Habitat & DistributionSecond most widely distributed plants in
the world after grassesMainly found in warm, moist placesAlso found in dry or seasonally cold
environments such as savannahs and semi-deserts
Found in rainforests, swampsWorldwide (except Antarctica): mostly
tropics in countries such as Guyana, Venezuela and Brazil; even the Arctic Circle and Africa
Parts of an Orchid Flower
General Characteristics of Orchids:
Pedicel Calyx Petals
Characteristics of Orchids:Distinguishing characteristics of the orchid are found in the flower.• The petal aka lip or labellum is opposite
the fertile stamen.• The fertile stamen or stamens are on one
side of the flower opposite the lip, making the flower bilaterally symmetrical.
• The pistil is in the middle of the flower.• Single anther is retained at the top of the
column to form a cap-like structure (in most orchids).
Characteristics of Orchids (con’t): Reduced filaments, anthers, style and stigma;
fused into one structure called the column
Characteristics of Orchids (con’t):
Stigma is in the form of a shallow depression on the inner sides of the column.
In the bud, the lip is oriented upward but as the flower matures, it usually ends up downward; process called resupination.
Outer whorl: 3 sepals Inner whorl: 3 petals
Characteristics of Orchids (con’t):Rostellum (flap of tissue covered with
sticky stigmatic liquid) separates the stigma and anther.
Primitive orchids – pollinia (contains many pollen) stick to stigmatic fluid on the insects’ backs because the orchids contain no rostellum.
Advanced orchids – pollinia caudicles are already attached to the rostellum; a portion comes off as a sticky pad known as the viscidium
Characteristics of Orchids (con’t): Fruits are dry capsules; small, numerous, dust-
like seeds that lack an endosperm (wind dispersal)
The seeds depend on fungus since the fungus penetrates the seed and provides it with nutrients to germinate and grow.
Orchids contain several types of nectaries, including the extrafloral types. Floral fragrances are diverse, from quite sweet to the smell of rotting liver.
Some nectaries are located on the side lobes of the lip and secretion along the groove of the lip occurs.
Economic Importance of Orchids
They are used mainly as ornamentals (to beautify the environment).
Their sweet extracts can be used in perfume production.
Orchids are used as food in Indonesia.Orchids have medicinal value in China
and Japan.Several species of orchids are used as a
glue substitute (derived from the pseudobulbs).
References: Raskoti, B. B.; 2013; Orchid Distribution; http://
www.ionopsis.com/distribution.htm; 22/09/2013 Welch-Keesey, M.; 2013; Just the Facts about
Orchids; http://www.indyzoo.com/SiteAssets/pdfs/HandoutA-OrchidFacts.pdf; 22/09/2013