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 Sambucus canadensis, L., L. standing for 
Linneus. 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 Coffee-tree genus con- 
tains only one species, 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. Ina 
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 
hybrid. 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 
