XXVlll INTRODUCTION TO BOTANY. 



resemble each other more than they do any other species ; the species so 

 hrou<i;-ht together are collectively called a Genus, and the common name 

 is the goiiric )iamc. Each sjiecies is fm-thcr distinguished from the others 

 of the same genus by the addition of an adjective epithet, or spec{fic 

 name. Every species has thus a botanical name of two words. In Latin, 

 the language usually used for the purpose, the tirst 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 fomiod being very numerous, they have been 

 grouped together on similar principles — associating those which resemble 

 each other most nearly — into Families or Natural Orders, to each of 

 which a name has been given. This is, however, for the purpose of study 

 or comparison. Li speaking of a species it is only necessary to give the 

 generic and specific names. Tlie name of a Natural Order or Family, in 

 Latin, is an adjective plvu-al, usually fonncd from the name of some one 

 tupical genus, generally the best known, the first discovered, or the most 

 marked. Thus Itanniiculacca' is the Order of which the Ramoicuhis is the 

 typical genus ; GeraniacccB the Order of the Geranium and its allies, etc. 



181. The niunber of species included in a genus, or the nimiber of 

 genera in an Order, is very unequal. Some genera contain biit 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 

 subdi\dsion is required. The names of the several groups most generally 

 adopted are as follows, beginning with the most comprehensive or highest 

 divisions : — 



Classes : 



Suhelasses or Alliances. 

 Natural Orders : 



Suborders. 



Tribes. 



Subtribes. 



Divisions. 



Subdivisions. 



Genera : 



Suhgoiera. 



Sections. 



Subsections. 



Species : 



Varieties. 



183. Classes, Orders, Genera, and their subdivisions, are called natural, 

 when, in forming them, all resemblances and diflerences are taken into 

 account, valuing them according to their importance ; artificial, when 

 resemblances and differences in some one, or verj' few particulars only, are 

 taken into account. 



IV. Collection-, Preservation, and Examination of Plants, 



18-i. Though j)lants 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, sjKcimens 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, 

 Jlou-crs (both open and in bud), and fruit (both young and mature). It is 

 not always, however, possible to gather such complete specimens ; but the 



