46 OUTLINE OF STRUCTURAL BOTANY 
ing characteristics common to all, would have less resemblances 
among the individuals than we find in the Species and if the seed 
of one member of the group were planted it would not produce a 
plant which would resemble all the members, but only members 
exactly like that which produced the seed. 
This secondary grouping is known as a Genus (meaning race, 
stock). It is the second step in our classification and the second 
easiest, for there are usually found between the species of a genus 
very obvious connecting features. 
But on much closer scrutiny we may collect these Genera into 
other groups with evident general resemblances shown either in 
general appearance or by the comparative study of one or more 
classes of organs. It is, in fact, by this latter method principally 
that this third grouping is determined and the groups are called 
Families. 
Even these Families may be united into larger groups and we 
have Orders, and the collection of Orders leads us to Classes, and 
these Classes finally form Divisions. 
Thus, the mushrooms, which are without flowers and without 
seeds, belong to one Division, while the violet, with its flower and 
its seed, belongs to another Division; and of the flowering and 
seeded plants we have the large group of plants with parallel veined 
leaves whose ovules have a single lobe, belonging to one Class, while 
the plants with net-veined leaves and two-lobed ovules belong to 
another Class. 
We may then arrange our groups of plants, from the most gen- 
eral to the most specific groups, as follows: 
Divisions. ‘Classes. Orders. Families. Genera. Species. 
It is found convenient in some cases to subdivide some of these 
groups, when the subdivisions are known as Sub-Classes, Sub- 
Families, etc., or, in the case of Species, as Varieties. 
In treatises and text-books during most of the nineteenth century 
it was the custom to arrange the sequence of Families according 
to a prevailing view of the perfection of the development of the 
plants from highest to lowest ; commencing with what were regarded 
as the most fully developed, the plants of the Ranunculus Family, 
and proceeding towards those less completely organized. 
This system of arrangement has, within the past few years, given 
way to the much more natural and more reasonable arrangement of 
finding the sequence of the Families in the gradual evolution of 
the organs of the plants. This system has not simply reversed 
the order of arrangement with which many of us have become fa- 
