XXViil INTRODUCTION TO BOTANY. 
resemble each other more than they do any other species; the species so 
brought together are collectively called a Genus, and the common name 
is the generic name. ach species is further distinguished from the others 
of the same genus by the addition of an adjective epithet, or specific 
name. very species has thus a botanical name of two words. In Latin, 
the language usually used for the purpose, the first word is a substantive 
usually of Greek origin and Latinized, and designates the genus; the 
second, usually a Latin adjective, indicates the species. 
180. The genera thus formed being very numerous, they have been 
grouped together on similar principles—associating those which resemble 
each other most nearly—into Fumilies or Natural Orders, to each of 
which a name has been given. This is, however, for the purpose of study 
or comparison. In speaking of a species it is only necessary to give the 
generic and specific names. The name of a Natural Order or Family, in 
Latin, is an adjective plural, usually formed from the name of some one 
typical genus, generally the best known, the first discovered, or the most 
marked. Thus Ranunculacee is the Order of which the Ranunculus is the 
typical genus; Geraniacee the Order of the Geranium and its allies, etc. 
181. The number of species included in a genus, or the number of 
genera in an Order, is very unequal. Some genera contain but one, 
others but two or three species; in others, several hundred species are 
associated together. There is a similar discrepancy in the number of 
genera in the several Orders. 
182. Orders are collected into Classes; and where Orders contain a 
large number of genera, or genera a large number of species, a further 
subdivision is required. The names of the several groups most generally 
sievies are as follows, beginning with the most comprehensive or highest 
visions :— 
Classes: Genera: 
Subclasses or Alliances. Subgenera. 
Sections. 
Natural Orders: Ruturstoas! 
Suborders. f 
Tiches! Species: 
Subtribes. Varieties. 
Divisions. 
Subdivisions. 
183. Classes, Orders, Genera, and their subdivisions, are called natural, 
when, in forming them, all resemblances and differences are taken into 
account, valuing them according to their importance; artificial, when 
resemblances and differences in some one, or very few particulars only, are 
taken into account. 
* 
IV. Cotiection, PRESERVATION, AND EXAMINATION OF PLANTS. 
184. Though plants can be most easily and satisfactorily examined 
when freshly gathered, yet as time will rarely admit of this being done, 
and as it is also desirable to compare with other plants previously observed 
or collected, specimens must be selected for leisurely observation at home, 
and for preservation for future reference. 
185. A botanical Specimen should be, as much as possible, an epitome 
of the species which it represents, and if the species be variable, several 
specimens are necessary. ‘To be perfect, it should have root, stem, leaves, 
flowers (both open and in bud), and fruit (both young and matwre). It is 
not always, however, possible to gather such complete specimens ; but the 
