1008. The points of resemblance between plants which constitute their affinity according to the Natural System are, however, very difficult to define. In fact, as Dr. Lindley observes, ' very different ideas of likeness and unlikeness are entertained by different observers. The common people can see no difference of moment between a daphne, a cherry, and a rhododendron, but call them all laurels, although a botanist fails to perceive their resemblance. On the other hand, there seems to the vulgar eye no connection between the hemp-plant and the mulberry-tree, and yet the botanist brings them into close alliance. Nor are these conflicting views confined to the ignorant and the uneducated ; such differences of opinion may be found among botanists themselves.' (Vegetable Kingdom, p. xxv.)
