Orchidaceae - Orchid Family

Orchidaceae - Orchid Family

Orchidaceae is a very large family that contains at least 20,000 species and 735 genera, distributed throughout the world except in the coldest areas, and most numerous in damp equatorial regions.
The flowers are the most highly evolved of the plant kingdom; they have three sepals and three petals and sometimes grow singly, but more usually appear with other flowers on spikes, growing up one side of the main stem, or all around the main stem, which may be upright or drooping.
The lowest petal of each flower, the lip, is usually large, and may be spurred, fringed, pouched, or crested. Orchid fruits are usually 1-chambered capsules with many very small seeds.
Many tropical orchids are epiphytes – attached to trees but feeding independently on decayed plant and animal remains and rainwater – but temperate orchids commonly grow on the ground.

General Key to Identify which Genus a Species Belongs to

1a. .	Plants lacking green stems and leaves, stems yellow to reddish-brown, underground parts coral-like.................						Corallorhiza
1b.	Plants with green stems and leaves................................						2
	2a.	Lower lip of flowers inflated, pouch-like......................					3
		3a. .	Leaves 2 or more, basal or on flowering stems, flowers white to yellow......................................				Cypripedium
		3b.	Leaves single, basal, flowers pink to purple..........				Calypso
	2b.	Lower lip of flowers not pouch-like.............................					4
		4a. .	Flowers with a spur projecting downwards from the base of the lower lip......................................				5
			5a. .	Flowers white to pale pink, spotted with purple........................................................			Orchis
			5b.	Flowers white to green, not spotted.............			6
				6a. .	Lip petal 3-lobed at tip, bracts much longer than flowers..............................		Coeloglossum
				6b.	Lip petal not lobed at tip......................		7
					7a. . .	Sepals 1-nerved, basal leaves usually withered at flowering time.............................................	Piperia
					7b. .	Sepals 3-nerved, basal leaves green at flowering time..................	Platanthera
		4b.	Flowers without spurs.......................................				8
			8a. . .	Flowering stems leafless, leaves in a basal rosette, dark green, mottled or striped with white veins...............................			Goodyera
			8b.	Flowering stems with some leaves..............			9
				9a. .	Leaves 2, opposite, egg-shaped to round, usually less than 5 cm long.......		Listera
				9b. .	Leaves several, alternate, oblong to linear, lower leaves more than 5 cm long...........................................		Spiranthes