120 SYSTEMATIC BOTANY. 



The names, Division, Class, Tribe, Cohort, Order, and 

 Family are not always used with exactly the same signifi- 

 catioa by different botanists, 



152. The system of nomenclature, perfected byLinnseus, 

 and used since his time, is binomial ; that is, every plant 

 is designated by a double name, the name of the genus 

 followed by the name of the species, both being Latin, or 

 Latinized words. Thus the botanical name of Black 

 Walnut is Juglans nigra, L.; of Sugar-Maple, Acer sao 

 char inum, Wang. ; of Ground Ivy, Nepeta Gleehoma, Benth., 

 etc. The specific name is generally an adjective, and, 

 therefore, is not to be capitalized, unless it is a proper 

 adjective, as in Sanguinaria Canadensis ; sometimes it is an 

 old substantive, or the name of a person, in which cases 

 the capital is retained, as in Magnolia Umbrella, Lam. ; 

 Phacelia Purshii, Buck. The generic name is a substan- 

 tive, always capitalized, and may be the old classical name, 

 as Platanus, Acer, Nepeta; a name formed from Latin, 

 Greek, or other words, as Trifolium (Lat. tri, three; 

 folium, leaf), Zea (Gr. zao, to live), Datura (Arabic 

 Tatorah) ; or the name of a person, as Claytonia (after 

 John Clayton, an early botanist of Virginia) ; Linncea 

 (after Linneeus, the immortal Swedish botanist, born 1707, 

 died 1778). The abbreviation of the author's name is also 

 added when botanical names are written. Thus, L., Wang., 

 Benth., in the names above are for Linrueus, Wangenhemn, 

 Beniham, who described and named the several species. 



153. Many attempts have been made to classify plants, 

 but until recently the arrangement was very artificial, in 

 as much as undue stress was laid on one, or a few charac- 

 ters, to the exclusion of all others. By this method plants, 

 very much unlike in general, were often brought near 



