86 



DOMESTIC BOTANY. 



ance. Be that as it may, it must be admitted that 

 natural families also consist of plants of very different 

 habits and appearance. Snowdrop and American aloes 

 for instance being associated in the same family, and 

 clover and acacia tree in another. But although such 

 is the case, they nevertheless agree in the character of 

 their flowers and fruit. It must, however, be under- 

 stood, that in any number of species constituting a family, 

 there are nevertheless often one or more which deviate in 

 some particular point from its normal character, as — to 

 have opposite leaves instead of alternate, while agreeing 

 in every other character. Therefore in describing and 

 characterizing families it is necessary to use modifying 

 words, as sometimes, rarely, often. 



According to the Linneean system, by simply examin- 

 ing the stamens and pistils of any plant its class and 

 order can be readily determined. But to be able to refer 

 plants to their respectis^e natural families much more 

 study is required, as the following will show. Linnaeus 

 being aware that his sexual system was quite artificial, 

 with the knowledge of the principles of natural classifi- 

 cation as pointed out by Bay, he in 1751 gave his views 

 of a natural arrangement, under which he classed all 

 plants then known to him under sixty-eight orders. 

 But the credit of scientifically defining the principles of 

 natural classification is due to A. L. Jussieu, a French 

 botanist, who in 1789 published a Genera Plantarum," 

 or Natural System of Plants, in which the whole are 

 arranged under 100 natural orders, comprehended under 

 15 classes, the primary characters being derived from 

 the seed having one, two, or no cotyledons, the corolla 

 being raonopetalous or polypetalous, and in the stamens 

 being hypogynous, epigynous or perigynous, which have 



