PRINCIPLES OF CLASSIFICATION. 123 
subdivide these again, Thus, in sub-class Polypetale we may 
put into one subdivision all those plants (chaps. I. and EELS}, 
the flowers of which have their sepals, petals, stamens, and 
carpels separately attached to the receptacle or thalamus, and 
forming the division Thalamiflore ; into a second, those in 
which the petals and stamens are attached to a hypogynous 
disc, called Discifloree ; and into a third, those in which the 
petals and stamens are on the top of the ovary, or are 
attached to the calyx (chap. IIT.), called Calyciflore. Sub- 
class Gamopetale divides into subdivisions Epigynee, in 
which the corolla is, as its name implies, fastened above the 
ovary, and Hypogyne, in which it is fastened under the 
ovary. 
Similarly, in Monocotyledons two great divisions may be 
noticed: firstly, those which have a more or less distinct 
perianth, called (from the frequent resemblance of this to 
petals) Petaloidez ; and, secondly, those, like grasses and 
sedges, which have almost or altogether lost the perianth, 
and have its place and function taken by scale-like bracts or 
glumes, and which are therefore called Glumifere. 
_ We may summarise this classification in a table thus :— 
Class I. Dicotyledons. 
Sub-class I. Polypetalw, petals free. 
Division I. Thalamiflorz, calyx inferior, petals and 
stamens hypogynous. 
Division II. Discifloree, calyx inferior, petals and 
stamens on a hypogynous disc. 
Division III. Calyciflore, calyx inferior or superiov, 
petals and stamens either perigynous or 
epigynous. 
Sub-class II. Gamopetalee, petals joined. 
Division I. Epigyne, corolla epigynous. 
Division Il. Hypogynex, corolla hypogynous. 
Sub-class III. Incomplete, perianth consisting of 
sepals only, or wanting. 
Class IT. Monocotyledons. 
Sub-class I, Petaloidz, with a more or less perfect 
perianth, which is often petaloid. 
Division I. Hpigynee, perianth superior. 
Division II. Hypogynz, perianth inferior. 
Sub-elass II. Glumiferz, perianth imperfect or want- 
ing, flowers placed in the axils of glumes. 
These sub-classes or divisions are formed of smaller groups 
variously called cohorts, tribes, or families, and these again of 
orders. The orders are sometimes broken up into swb-orders, 
which in their turn consist of genera, and these are formed of 
one or more species. 
