Saprophytic Plants

Collier's New Encyclopedia (1921)

plants that feed on decaying organic matter. In common with many of the PARASITIC PLANTS (q. v.), which are plants that live on or in and at the expense of other organisms, they are often devoid of chlorophyll. The reason of this peculiarity is obvious; chlorophyll being the material used by ordinary plants for the decomposition of the carbonic acid of the air in order that they may retain the carbon, and with it build up all the carbon compounds characteristic of organic nature, it is plain that those plants which obtain their carbon compounds readydo not remade up to a certain point oint quire chlorophyll from which to manufacture them. If the saprophytism be not complete or "pure" there will be at least some chlorophyll remaining, as in the flowering axis of the orchid Neottia. Saprophytes may obtain their nourishment and especially their carbon compounds either from the remains of dead organisms or from organic compounds formed by living organisms. The Fungi ung that live on the bark of trees and the leaf-soil of forests and meadows (e. g., mushrooms) are examples of the former case; those that feed on the juice of fruits and sugary e solutions ( . g., molds and yeasts) of the latter case. Fungi may be physiologica classified as parasites and saprophytes; but this classification does not coincide' with a morphological one. Further, there are certain species which lie between the two extremes, and these may be described as parasites which may become wholly in part saprophytic through the or whole course of their development or during certain stages of it; and also there are saprophytes which, with the same variations, may become parasitic. The external conditions necessary for the commencement of germination of Fungi are the same as those needful to the germs and seeds of other plants; they are a certain temperature, a supply of oxygen and of water, in certain cases a supply of nutrient substances. The spores of the Perennosporeæ and of the Üredineæ germinate on drops of pure water; nutrient solutions may even be a hindrance. The Mucorini, on the other hand, emit only rudimentary germ tubes in pure water; they require a nutrient Most Fungi solution for germination. ion. vary toward one extreme or other according to the species.