fore, if we merely state that the species represents a dy- 
namic, adaptive peak in evolution. Any taxonomic group 
above this level, in order to express a meaningful expan- 
sion, must represent further dynamic macro-units or en- 
larged adaptive peaks (which are the results of the co- 
action and coaptation of the basic units), because if these 
higher units are merely categories of convenience (as most 
of them are today) they will hinder rather than broaden 
our perspective and comprehension of the evolutionary 
makeup of our object of study. 
We have to keep constantly in mind that living species 
are scanty representations of all the possible modifications 
and combinations that may have occurred in nature, al- 
though those types which have been eliminated by selec- 
tive pressures still contributed to the formation of present 
species. Therefore, when we study a group of plants, we 
find that its basic units (i.e. species) are connected by a 
series of trends which are radiating in various directions, 
forming areticulate pattern. In visualizing this reticulate 
pattern in a three-dimensional perspective, we find that 
the connective trends progressively decrease as we ad- 
vance towards higher levels, but that this decrease never 
terminates in complete elimination. 
Such a dynamic and 3-dimensional structure (vaguely 
resembling the molecular structure of a crystal) cannot 
be projected into a 2-dimensional perspective without 
destroying, or at best distorting, its salient features. 
All of us, from time to time, have felt and recognized 
the presence of such a system, but our conventional mind 
with its categorizing instinct continuously interferes 
with and obscures our vision. I wish to make it clear 
that I fully recognize the necessity of categories of con- 
venience, but I strongly object when these categories of 
convenience are employed as the basis of a so-called 
‘“‘natural’’ system; and this is what has happened in the 
case of the Orchid family 
[ 59 ] 
