Perhaps the most famous botanist of all time was Carolus Linnaeus. While commonly called Linnaeus, he was a Swede whose real name was Karl von Linné. His great contribution was to devise the binomial system for naming plants that is still used today. He gave every plant only two names, the first for its genus and the second for its species. Aster, for instance, is the genus of a group of plants that have many characteristics in common and are closely related. But with more than 250 different asters in this genus, the only way you can tell one from the other is to know what species it is. The specific epithet, or species name, further describes the plant by its characteristics or by who discovered it or where it grows. Linnaeus used the international language of educated people, Latin. Thus Aster alpinus is the name of a rock-garden plant from the mountains. Aster novae-angliae is the New England aster.
The great advantage of the Linnaean system is that no two species of plants in the world have the same name. This eliminates the confusion that is often caused by using common names, since the same plant may have more than one common name, and the same common name may be used for different plants. For example, the vine Solanum dulcamara is usually called nightshade but is also called bittersweet. On the other hand, the vines best known as bittersweet are not Solanum at all but Celastrus orbiculatus (Oriental bittersweet) and Celastrus scandens (American bittersweet).
Although his plant taxonomy had many advantages, it was based solely on the number and arrangement of the reproductive organs; a plant's class was determined by its stamens (male organs), and its order by its pistils (female organs). This resulted in many groupings that seemed unnatural. For instance, Linnaeus's Class Monoecia, Order Monadelphia included plants with separate male and female "flowers" on the same plant (Monoecia) and with multiple male organs joined onto one