CLASSIFICATION. 127 



A Genus comprehends one or more species, grouped together on 

 account of some resemblance in situation, proportion, and connexion 

 of the organs which constitute the flower. Any one species of a 

 genus may be regarded as a type or example of the others; we may 

 easily refer species which we have not studied to their proper genus, 

 by a knowledge of any one species of that genus. Some genera 

 appear to be distinctly marked by nature ; the various species of the 

 rose form a beautiful genus which is known to all, although every 

 one might not be able to describe it to others in such a manner as 

 to be understood ; it is chiefly distinguished by its urn-shaped and 

 fringed calyx. 



The generic names of plants are derived from various circum- 

 stances ; in some cases from a peculiarity in the form or colour of 

 the corolla, or some property of the plant ; and some are named from 

 distinguished persons. Thus Iris (flag) is named from Iris the rain- 

 bow, on account of its various shades of colour. DigitaUs (fox- 

 glove) is named from digitus, a finger, on account of the shape of 

 its corolla, which is Uke the finger of a glove. Convallaria (lily 

 of the valley) is named from a Latin word convallis, signifying, in 

 the valley. Teucrium (germander) is named in honour of Teucer, 

 a Trojan prince. The English name, germander, is supposed to 

 have originated from the word Scamander, the name of a river of 

 ancient Troy. The name of the great Linnaeus is commemorated 

 in a beautiful and modest flower, called the Linncea borealis* 



Specific names are adjectives; generic names are nouns. The 

 specific name sometimes indicates the number of leaves, as orchis 

 bifoiia, (bifoha, signifies two leaves ;) or the colour of the corolla, 

 as VIOLA tri-colour, (three-coloured violet ;) or the form of the root, 

 as soLANUM tuberosum, (with a tuberous root.) Specific names are 

 often derived from the names of persons ; thus a species of Origa- 

 num is named tournefortii, after its discoverer Tournefort. 



The system of Linnaeus may be illustrated by the following com- 

 parison ;— as. 



Individual persons compose Families, 

 Famines " Towns, 



Towns " Counties, 



Counties '* States. 



Individual plants compose Species, 

 Species ■ " Genera, 



Genera " Orders, 



Orders " Classes. 



Thus, as individual piersons are the real existences which make 

 up a state ; so are individual plants the real existences which com- 

 pose classes ; the words town and county, genus and order, being 

 general terms used to designate certain circumstances of these men 

 and plants. 



Natural Families. 



Afl;er having analyzed a number of plants, you will begin to ob- 

 serve a striking resemblance in many genera, and your own minds 

 win suggest the propriety of arranging them into groups, without 

 any reference to the artificial class or order where they may have 



* Borealis, signifying nor^/iern, has reference to the situation of the country which 

 gave birth to Linnaeus, The I^innaea borealis is not uncommon in New England, and 

 has been found on an island in the Hudsori, near Troy. 



What is a genus 7 — A knowledge of one species enables us to recogriise all other 

 Bpeciesof the same genus— Derivations of generic names — Iris— Digitalis— Teucrium 

 — Linnaea borealis— Specific names— Natural famihes. 



