NATURAL SYSTEM. 173 



SECTION IL-STSTEMATIO BOTANY. 



PART FIRST.— TAXONOMY, OR CLASSIFI- 

 CATION. 



LESSON XXXIV. 



NATURAL SYSTEM. 



420, 421. Natural System. 422.' Natural Analysis ; its Eules ap- 

 plied to the Olive; 423, and to the Sage. 424. Orders. 425. Sub- 

 Orders, Tribes. 426. Varieties, Eaces. 427. Wild Wheat. 428. Hy- 

 brids. 429. Scale of Classification. 430. Herbarium. 



420. The Natural System is so called because it groups 

 plants according to their natural resemblances and — as far 

 as we can discover it — ^their common origin from an 

 ancestral type. 



421. Its principle was discovered by Antoine Laurent de 

 Jussieu, of France (1748-1836), who was a Member of the 

 Academy of Sciences and Professor in the Garden of Plants. 

 Jussieu made faithful and exhaustive comparisons among 

 plants of every type then known, but especially among 

 seven of the best known Orders, — Grasses, Lilies, Labiates, 

 Composites, Umbelliferse, Leguminosse, and Cruciferse. He 

 found that their characters must be " weighed, not counted," 

 to use his own words; that the fundamental principle of all 

 order in nature is the Relative value of characters, — a prin- 

 ciple so simple we might wonder how it chanced to remain 

 so long unnoticed if we did not remember that other prin- 

 ciples equally simple, such as gravitation, etc., were un- 

 known three hundred years ago. 



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