The cases in which the diffusion of fruits and seeds is effected by their being sticky are less numerous, and we have no well-marked instance among our native plants. The common plumbago of South Europe is a case which many of you no doubt have observed. Other genera with the same mode of dispersion are Pittosporum, Pisonia, Boerhavia, Siegesbeckia, Grindelia, Drymaria, etc. There are comparatively few cases in which the same plant uses more than one of these modes of promoting the dispersion of its seeds, still there are some such instances. Thus in the common burdock the seeds have a pappus, while the whole flower-head is provided with hooks which readily attach themselves to any passing animal. Asterothrix, as Hildebrand has pointed out, has three provisions for dispersion: it has a hollow appendage, a pappus, and a rough surface. The next point is that seeds should find a spot suitable for their growth. In most cases, the seed lies on the ground, into which it then pushes its little rootlet. In plants, however, which live on trees, the case is not so simple, and we meet some curious contrivances. Thus, the mistletoe, as we all know, is parasitic on trees. The fruits are eaten by birds, and the droppings often, therefore, fall on the boughs; but if the seed was like that of most other plants it would soon fall to the ground, and consequently perish. Almost alone among those of English plants it is extremely sticky, and thus adheres to the bark. I have already alluded to an allied genus, Arceuthobium, parasitic on junipers, which throws its seeds to a distance of several feet. These also are very viscid, or, to speak more correctly, are imbedded in a very viscid mucilage, so that if they come in contact with the bark of a neighboring tree they stick to it. Among terrestrial species there are not a few cases in which plants are not contented simply to leave their seeds on the surface of the soil, but actually sow them in the ground. I have already alluded to the Cardamines, the pods of which open elastically and throw their seeds some distance. A Brazilian species, C. chenopodifolia, besides the usual long pods, produces also short, pointed ones, which it buries in the ground. Arachis hypogæa is the ground-nut of the West Indies. The flower is yellow and resembles that of a pea, but has an elongated calyx, at the base of which, close to the stem, is the ovary. After the flower has faded, the young pod, which is oval, pointed, and very minute, is carried forward by the growth of the stalk, which becomes several inches long and curves downward so as generally to force the pod into the ground. If it fails in this, the pod does not develop, but soon perishes; on the other hand, as soon as it is underground the pod begins to grow and develops two large seeds.