We find, much to our encouragement, that there are a few plant families with which we at once become familiar; and their marked features impress us as those of unusual faces that have to be seen but once to be clearly remembered. The greater number of families, however, and their branches are not so readily known. The least little variation in a plant's manner of growth will cause it to be separated from its relatives, even if it has to be regarded as a new species.

The first Latin or Greek word of a plant's scientific name is the name of its genus: its family name. The second word is an adjective that denotes its species and is usually significant of some characteristic or history with which it is connected. These names are too valuable to be overlooked, and as much as possible they should be memorised. The world over, a plant's scientific name is the same, while the common English names often change not only with country, but with state and town. Following are a few traits of families that are among those most easily recognised: