In nature, fungi play an important part in the decomposition of organic debris. Dead wood is quickly invaded by fungi and its hard texture is soon destroyed. Throughout the world there are fungi which live as saprophytes on organic matter in the soil and a more or less universal range of fungus species is always present. Not only do these fungi break down the organic material but they also help to maintain a soil texture. A special environment exists on or very near the surface of roots and the fungal flora of this “rhizosphere” differs from that in the rest of the soil. Specific fungi also grow in the association with specific plants of higher groups and often enter into the tissues of the living root without any noticeable pathogenic effects. The physiology of such a “mycorrhizal” relationship is not really clearly understood, but it is generally thought that under favourable conditions the other plant gains through the relationship with the fungus. In New Zealand only a few cases of mycorrhiza in our endemic plants have been investigated, but casual observations suggest that it is of common occurrence, especially in the Ericaceae plants (e.g., Pernettya and Gaultheria). In our exotic pine plantations fructifications of fungi associated with conifers of North America and Europe are extremely common, e.g., Amanita miscaria and Boletus granulatus, and it is apparent that these fungi have a mycorrhizal relationship with the pines.