PREFATORY REMARKS. 
The natural order called Orchidacea3 consists of plants extremely 
dissimilar in habits, appearance, and structure, but agreeing in being 
organized upon the type of Endogens, in having gynandrous flowers, 
and an inferior polyspermous ovary. Of these three characters there is 
an infinite number of modifications, the nature of which it is the purpose 
of the following general description in part to explain. 
In habit they are terrestrial or growers in the earth, epiphytal or 
growers upon the surface of trees, rocks, stems, and other bodies, or 
apparently true parasites. While however it seems probable that such 
plants as Neottia, Corallorhiza, and Gastrodia are of the latter kind, there 
is no direct evidence of the fact. 
Reticulated cellular tissue is common in all the foliaceous organs; 
and raphides, collected in cubical bundles, occur in every part, except in 
those immediately connected with the act of impregnation. They have 
been found by Dr. Brown in the stigma, but 1 have not seen them in the 
conducting tissue of that organ, although they undoubtedly occur in the 
styles 
The roots are of the following kinds. Firstly, annual slender fibres, 
simple or branched, of a succulent nature, incapable of extension, and 
burrowing under ground, as in the genus Orchis ; secondly, annual fleshy 
tubercles, round or oblong, simple or divided, as in the various species 
of the same genus : they are always combined with the first, and appear, 
from their containing amylaceous granules in large quantity, to be in¬ 
tended as receptacles of matter fit for the nutrition of the plant: tuber¬ 
cles of this kind always have a bud at their extremity, and may be con- 
