Monocotyledons with Petaloid Flowers. 
119 
Natural Order 
ORCHIDAC EJE. Tab. 93. 
Diagnosis. —Herbs with sheathing leaves. Flowers irregular. Stamens 
1 or 2, aclnate to the style. Ovary inferior. Seeds indefinite, exalbuminous, 
without distinction of radicle and cotyledon. 
Distribution. —A very large Natural Order, widely distributed both in Temperate and Tropical 
countries ; in the former the species are usually rooted in the earth ( terrestrial ), while in hot humid 
climates a large proportion of the species are epiphytal, growing upon the bark of trees, though without 
deriving nourishment from their juices as do parasites. 
Number of British Genera, 17; Species, 36. 
Stem in British Orchids erect, simple, succulent; in many tropical epiphytal species variously thickened, 
forming pseudo-bulbs. 
Leaves sheathing, membranous, succulent or coriaceous, usually entire and glabrous ; wanting (reduced to 
coloured scales) as in Coral-root ( Gorallorhiza ) and Bird’s-nest ( Neottia ), British species growing amongst decomposing 
vegetable matter. 
FLOWERS bracteate, racemose or spicate in nearly all British genera ; panicled or solitary in some exotic genera; 
usually inverted ( resupinate ) so that the uppermost (posterior) leaf of the perianth becomes apparently the lowest 
(anterior) by the partial twisting of the ovary or pedicel. 
Perianth-limb of 6 segments, 3 outer (sepals) and 3 inner (petals) ; the median lower petal (lip or labellum) 
almost invariably different in form from the rest and usually larger; in Common Orchis with the base (attached end) 
of the lip prolonged into a spur. 
