Elementary botany . tion of moulds.—In our study of mucor, as we have seen, the growing or vegetative partof the plant, the mycelium,lies within the substratum,which contains the foodmaterials in solution, and theslender threads are thusbathed on all sides by mycelium absorbs thewatery solutions throughoutthe entire system of ramifica-tions. When the uprightfruiting threads are devel-oped they derive the materialsfor their growth directly fromthe mycelium with whichthey are in connection. Themoulds which grow on de-caying fruit or on otherorganic matter derive theirnutrient materials
Elementary botany . tion of moulds.—In our study of mucor, as we have seen, the growing or vegetative partof the plant, the mycelium,lies within the substratum,which contains the foodmaterials in solution, and theslender threads are thusbathed on all sides by mycelium absorbs thewatery solutions throughoutthe entire system of ramifica-tions. When the uprightfruiting threads are devel-oped they derive the materialsfor their growth directly fromthe mycelium with whichthey are in connection. Themoulds which grow on de-caying fruit or on otherorganic matter derive theirnutrient materials in the sameway. The portion of themould which we usually seeon the surface of these sub-stances is in general the fruit-ing part. The larger partof the mycelium lies hiddenwithin the subtratum. 186. Nutrition of para-sitic fungi.—Certain of thefungi grow on or within thehigher plants and derive their food materials from, them and at their ex-pense. Such a fungus is called a parasite, and there are a large number. Fig. 75-Carnation rust on leaf and flower stem,graph. From photo- HOW PLANTS OBTAIN FOOD. 87 of these plants which are known as parasitic fungi. The plant at whoseexpense they grow is called the host. One of these parasitic fungi, which it is quite easy to obtain in green-houses or conservatories during the autumn and winter, is the carnationrust \Uromyces caryophyllinus), since it breaks out in rusty dark brownpatches on the leaves and stems of the carnation (see fig. 75). If we makethin cross sections through one of these spots on a leaf, and place them for a
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