310 THE VEGETABLE WORLD. 
closely resemble the Aerides in habit ; their flowers are produce 
in long graceful racemes, often a foot and a half long, springing 
from the axils of the leaves. 
Oncidium is another extensive genera belonging to the Vandew ; 
they are chiefly natives of tropical America. The prevailing 
colour of their flowers is yellow spotted with rich reddish brown, 
and they are known by their broad labellum, more or less lobed, 
distinct from the column, and furnished at the base with a tuber- 
culated disk, spreading sepals and petals, with a membranous ear 
on each side of the column, and two pollen-masses attached to @ 
long caudicula, which give the plant a grotesque resemblance to the 
Butterfly, the name it bears. In their native forests these Epiphytes 
wholly overrun the trees, clasping them round, and covering them 
from top to bottom with their brilliant and grotesque flowers. 
The OpHrypEx have fleshy, bulbous roots, with radical fibres, 
leafy stem, anther continuous with the column, and the pollen-mass 
agglutinated and attenuated into a pedicel. In Orchis and 
Gymnadenia the lip has a spur, in Ophrys it is thick and spurless, 
in Habenaria the spur is very long; in Aceras the outer and inner 
divisions converging, form a hood, lip in three linear divisions and 
spurless. This and the following group are natives of temperate 
Europe, many of them of the British Islands. 
As a representative of the family we may take the plant 
known in this country and in the north of France, commonly call 
the Flower of Pentecost, or the spotted Orchis, Orchis eae? 
(Fig. 360). The floral envelope of this species is composed ° 
so well 
_ six petal-shaped pieces, disposed alternately in two rows he : 
361). Of the three exterior pieces, two are slightly lateral, eo 
middle one is curved forward in such a manner as to form, W! 
two divisions of the internal ventricle, a sort of casque oT helmet. 
The third division has, on*the contrary, a shape peculiar to itself; 
on the upper side it presents the appearance of a large bao ss 
apron, prolonging itself below into a sort of spur. This 18 
labellum, or lower lip, of the flower. The corolla is then essentially : 
irregular. When the six pieces of the floral envelope are Temov”” 
a central column becomes visible, having in front two cells, 
longitudinal openings of which face the apron. Below, an 
square cup, glossy and viscous, is observable. If we ope? ©” 
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