g INTRODUCTION. 
Originally, Darwin tells us, the flower consisted of “ fifteen 
organs, arranged alternately, three within three, in five whorls 
or circles; three sepals, three petals, six anthers in two circles 
(of which only one belonging to the outer circle is perfect in 
all the common forms) and three pistils, with one of them 
modified into the rostellum. Of the existence of three of the 
anthers in two of the whorls, R. Brown* offers no sufficient 
evidence, but believes that they are combined with the labellum 
whenever that organ presents crests or ridges. The amount 
of change these flowers have undergone from their parental 
or typical form is enormous. Organs are used for purposes 
widely different from their proper use,—other organs have 
been entirely suppressed or have left mere useless emblems of 
their former existence.’’ Two stamens belonging to the outer 
circle, that were or became petal-like, have united with a real 
petal to form the lip. Seven organs have united to form the 
column,” of which three alone perform their proper function, 
namely one anther and two generally confluent stigmas,— 
with the third stigma modified into the rostellum and inca- 
pable of being fertilized —and with three of the anthers no 
longer functionally active, but serving either to protect the 
pollen of the fertile anther, or to strengthen the column, or 
existing as mere rudiments, or entirely suppressed. To trace 
the gradations perfectly between the several species and groups 
of species in this great and closely-connected order, all the ex- 
tinct forms which have ever existed along many lines of descent 
converging to the common progenitor would have to be called 
into life.” + 
The flower of an Orchid may be solitary, or one of a cluster, 
and is furnished with a bract, a kind of little leaf that springs 
from the point where the flower stem joins the main stem. 
Sometimes petals and sepals unite to form a hood or roof over 
* A noted authority on this special subject. 
+ ‘* The Fertilization of Orchids.’’ 
