( 90 



BOTANICAL CLASSIFICATION OF PLANTS. 



The Linnean system of classification is founded on the stamens and 

 pistils of flowers. All plants are thus divided into 2 great divisions, 

 the phenogamous, or those plants having apparent flowers, or sexes, 

 and comprehending the first 23 of the 24 classes of Linnaeus, and 

 cryptogamous, the 24th class, comprising all plants with non-apparent 

 flowers or sexes. Some include these in the 21st class. 



The characteristics of classification used by Linnaeus were of 3 

 kinds : 1st factitious, made, or artificial ; 2d, essential character ; 

 i. e. a peculiar character of one genus, distinguishing it from all others ; 

 and 3d, natural character the general aspect or appearance of plants, 

 by which persons form some classification in their minds independent 

 of rules, etc. 



Jl natural family is composed of several genera having some com- 

 mon marks of resemblance, somewhat like artificial orders. Families, 

 truly natural, are such as to enable any one without the aid of science 

 to recognize them, as with the umbellate family, composed of dill, fen- 

 nel, caraway, etc., from the form of the seed-stem and branches, (like 

 an umbrella.) Other families are similarly distinguished by the form 

 of the corollas, as labiate, (like the lips,) cruciform, (like a cross,) 

 umbellate, (like an umbrella,) corymbiferous, leguminous, etc. 



The artificial classification is such that genera, unlike in general ap- 

 pearance, are classed together by the number of their stamens and 

 pistils, as the tulip and bullrush in order 1, class 8, and the beet and 

 elm in order 2, class 5. Still, this, though more difficult than the 

 natural classification, is essential to botanical arrangement, as great 

 numbers of plants cannot otherwise be arranged. It is like a diction- 

 ary, by turning to which we learn the character of plants, their habits 

 and qualities ; and the natural method is compared to the grammar 

 of botany. 



The rules of botanical science are 1st, that botanical classification 

 results from an examination and comparison of plants. 2d, every or- 

 ganic peculiarity in individual plants, establishing a resemblance or 

 difference, is a character or sign, by which it may be known and dis- 

 tinguished. 3d, the presence of an organ, or its absence, is a character. 

 4th, the presence of an organ is a positive character, and its absence 

 a negative character. 



Botany rests on constant characters and these may be isolated or co-ex- 

 istent : as a butter cup" has a nectary in the form of a scale, a charac- 

 ter, which though constant, is isolated, not being necessarily connected 

 with any other characteristic. The calyx of the blue-bell" adheres 



