Sentence Examples


  • The group has until recent years been regarded as comprising three classes distinguished by well-marked physiological featuresthe Algae (including the Seaweeds) which contain chlorophyll, the Fungi which have no chlorophyll and therefore lead a saprophytic or parasitic mode of life, and the Lichens which are composite organisms consisting of an alga and a fungus living together in a mutual parasitism (symbiosis); Bacteria were regarded as a section of Fungi.
  • Such a relationship is known as symbiosis, and the large majority of the cases of so-called parasitism among green plants can be referred to it.
  • The union taking place underground, while the bulk of both partners in the symbiosis rises into the air, renders the association a little difficult to see, but there is no doubt that the plants in question do afford each other assistance, forming, as it were, a kind of partnership. The most pronounced case of parasitism, that of Cuscuta, the dodder, which infests particularly clover fields, appears to differ only in degree from those mentioned, for the plant, bare of leaves as it is yet contair.s a little chlorophyll.
  • In its systematized form, as a branch of botanical study, it is of recent date, and, as now understood, the subject first received special attention about 1850, when the nature of parasitism began to be intelligible; but many disjointed references to diseased conditions of plants had appeared long before this.
  • Instances of what we may term tolerated parasitism, where the host plant seems to accommodate itself very well to the presence of the Fungus, paying the tax it extorts and nevertheless not succumbing but managing to provide itself with sufficient material to go on with, are not rare; and these seem to lead to those cases where the mutual accommodation between host and guest has been carried so far that each derives some benefit from the associationsymbiosis (see FUNGI).

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