THE CLASSIFICATION OF PLANTS 229 



250. Genus and Species. — Such a group as that of the 

 buttercups is called a genus (plural genera), while the 

 various kinds of buttercups of which it is composed are 

 called species. The scientific name of a plant is that of the 

 genus followed by that of the species. The generic name 

 begins with a capital, the specific does not, unless it is a 

 substantive. After the name comes the abbreviation for 

 the name of the botanist who is authority for it; thus the 

 common elder is Samhucus canadensis, L., L. standing for 

 Linnaeus. Familiar examples of genera are the Violet 

 genus, the Rose genus, the Clover genus, the Golden-rod 

 genus, the Oak genus. The number of species in a genus 

 is very various, — the Kentucky CofEee-tree genus con- 

 tains only one sp.ecies, while the Golden-rod genus com- 

 prises more than forty species in the northeastern United 

 States alone. 



251. Hybrids. — If the pollen of a plant of one species 

 is placed on the stigma of a plant of the same genus but a 

 different species, no fertilization will usually occur. In a 

 large number of cases, however, the pistil will be ferti- 

 lized, and the resulting seed will often produce a plant 

 intermediate between the two parent forms. This proc- 

 ess is called hybridization, and the resulting plant a 

 hylrid. Many hybrid oaks have been found to occur 

 in a state of nature, and hybrid forms of grapes, orchids, 

 and other cultivated plants, are produced by horticul- 

 turists at will. 



252. Varieties. — Oftentimes it is desirable to describe 

 and give names to subdivisions of species. All the culti- 

 vated kinds of apple are reckoned as belonging to one spe- 

 cies, but it is convenient to designate such varieties as the 



