Mr. J. P. Mansel Weale mentions that in Karoo many plants have tuberous roots above the soil resembling stones so perfectly that it is almost impossible to distinguish them. The tubers of the potato itself in its native home may perhaps be protected in this way. The last-mentioned observer has also noted a labiate plant, Ajuga orphrydis, in South Africa, which bears a strong resemblance to an orchid. As this is the only species of bugle in the district, Mr. Wallace thinks the flower profits by the mimicry and succeeds in attracting the insects required for its fertilization. A species of balsam at the Cape has also acquired an orchid-like aspect; Tillandsia Usneoides, one of the pineapple family, grows on trees in tropical America, and has a resemblance to a shaggy lichen so marked that it is generally mistaken for a plant of that order. The fly agaric, our most conspicuously colored fungus, according to Dr. Plowright, is closely imitated by a parasitic flowering plant, Balanophora volucrata, the scarlet cap, the dotted warts, the white stem and volva being all accurately represented. The curious shapes of some exotic orchids are probably advantageous from their resemblance to insects and birds. One of our native orchids, Listua ovata, has a flower which in shape decidedly resembles a species of beetle, Grammoptera lævis, by which it is fertilized. Perhaps in this case the insect mimics the flower, as certainly happens with a pink-colored mantis in Java, which so exactly resembles a pink orchid that butterflies are attracted to it in mistake. The insect is carnivorous, and lies in wait for its prey, which is easily secured by the help of this strange disguise. Mutual resemblances of this description are rather characteristic of the Orchidaceæ. From their resemblance, real or fanciful, to butterflies, moths, bees, spiders, etc., various species of Habenaria, Neotinea, and Ophrys derive their names--the butterfly, spider, bee and fly orchises. In the orchid Ophrys muscifera are two little protuberances, regarded by the late H. Müller as pseudo-nectaries. Of this class of deceptive contrivances, however, we have a better example in Parnassia palustris, one of the saxifrages. This flower has five fan-like scales alternating with the stamens; the margins of the scales are fringed with hair-like processes, and each hair is capped with what appears to be a drop of honey. These are really hard, dry knobs, but so much do they resemble drops of honey that flies lick them before discovering the imposture. The intention of these sham nectar-drops may either be to decoy unprofitable guests from the real nectar, of which a limited supply is produced in the hollow of each scale, or to advertise it for the benefit of the more intelligent visitors.