chlorophyll, and manufacture their own food; and it is with some little surprise, therefore, that when we come to the Seed Plants, the highest group of all, we find, though in relatively few cases, a reversion to the animal trait of using organic food. Some of our woodland plants have taken so entirely to a diet of leaf-mould that they have discarded the apparatus which would enable them to manufacture their own food. Chlorophyll, the magic wand by means of which the inorganic is transformed into the organic, and also leaves, the mills wherein the transformation takes place, are absent from these plants. For instance, the Bird’s-nest Orchis (_Neottia Nidus-avis_), [Illustration: FIG. 31.--BIRD’S-NEST ORCHIS (NEOTTIA NIDUS-AVIS). 1/2.] sends up from a mass of fleshy roots a bare brown stem about a foot high, bearing a spike of brown flowers, the whole being so much of the same colour as the dead beech leaves among which the plant is usually found that it may easily be passed over. It is quite incapable of manufacturing its own food, but feeds on the decaying vegetable material which was manufactured by the trees under whose shadow it grows. It is but a step from _saprophytes_ such as this to _parasites_, which feed, not on dead, but on living organic matter. In the case of the higher plants, the hosts are always themselves plants, though, as pointed out on p. 78, they are, in the case of the Fungi, sometimes animals. One of the most interesting of these parasites is, like the Bird’s-nest Orchis, found in woods--the Yellow Bird’s-nest (_Monotropa Hypopitys_). This is, like the last, a leafless plant devoid of chlorophyll, sending up from a tangled root-mass one or more pale yellow stems, each bearing a drooping raceme of flowers of the same colour. The flowers show affinities to the Heath family (_Ericaceæ_), but the plant differs much from any other member of that Order. The Yellow Bird’s-nest is always found associated with the _mycelium_, or cobwebby underground portion, of a fungus, on which it appears to be parasitic. The fungus is in turn a saprophyte, and the Seed Plant feeds at second hand, so to speak, on decaying vegetable matter. This parasitism of a seed plant on a fungus is a very exceptional case. A more frequent type is offered by the Broomrapes (_Orobanche_), which we may find in meadows, etc., growing on Clover, Thyme, Ivy, and so on. These resemble the Bird’s-nest Orchis in sending up a stout leafless stem crowned with a spike of flowers. The different species display almost every colour except green, being red or brown or purple or yellow, and one blue. These plants live by attaching themselves to the roots of their host, and drawing in the nourishment they need for their own growth--robbery pure and simple. The seeds of the Broomrapes are very numerous and very light, and of singularly primitive structure. When they develop, they produce, not a young plant with root and stem, but a delicate spiral