146 ORCHIDACEAE 
Order VII.—ORCHIDACEAE. Orchidaceous Plants 
Of this order there is, in our region, only one family. 
ORCHIDACEAE. Orcuip FAmtIty | 
Among the Monocotyledonous plants the orchid family is pe- 
culiar in being that in which the flowers are always irregular. 
The perianth is of two rows of flower leaves, an outer, the calyx, 
of 3 segments which are alike or very nearly so and an inner, the 
corolla, also of 3 generally very unequal parts. The two side 
segments are nearly alike, but the middle or upper one is unlike 
the others and generally forms a lip, simple or fringed, or a boat- 
like pouch, and is often extended into a long spur. This upper 
segment, by the twisting of the ovary or of the flower pedicel 
may become the lower one. This upper lip differs from the other 
segments, not only in form and size but it is often strikingly in 
contrast in its color. Of the stamens, only one is, as a rule, de- 
veloped, but in Cypripedium two are fertile. The stamen or the 
two stamens grow in union with the pistil, forming what is known 
as the column. This arrangement brings the pollen bearing an- 
ther directly over or behind the stigma. The ovary is, contrary 
to the general rule with monocotyledonous plants, entirely in- 
ferior to all the parts of the flower, is elongated and in nearly all 
cases twisted, the torsion in general being 180°, while in some 
foreign species the rotation is fully 360°. 
In Cypripedium the bending of the flower stalk serves the same 
purpose as does the torsion of the ovary in other genera. The 
one-celled ovary is divided by three deep partitions to which are 
attached the very numerous small seeds. Orchidaceous plants are 
all perennial, the bulb for the succeeding year forming at the side 
of the bulb of the current year. Leaves generally from the stem 
and alternate but sometimes all from the root or opposite on the 
stem or even in whorls on the stem, they are parallel nerved. 
Flowers in a slender spike or loose broadened cluster or, less fre- 
quently, solitary. 
There are over 5000 known species of orchidaceous plants, the 
great majority of which are found in tropical climates, the most 
of these latter being air plants, finding their homes on the branches 
of trees and deriving their nourishment largely through the long 
trailing aerial roots. In our region all the species are plants 
having their roots in the soil or in wet mosses. 
