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of the plant are neither more nor less than a fungus which has 

 seized upon the Algae (a colony of them), made slaves of them, and 

 indeed, established itself upon them as a parasite ! But you will 

 be eager to know if this teaching, this Fungus- alga theory, as it is 

 called, rests upon any well-ascertained facts. In brief the evidence 

 is this. Many fungi produce their spores in little asci or thecas or 

 sporangia, and are called ascomycetout, ascosporous or thecasporous. 

 The spores of lichens are produced exactly in the same manner, 

 and have no connection with the gonidia — therefore they appear to 

 belong to the Fungus. Again the gonidia are said to be real 

 Algce, some of them well-known to exist quite independent of the 

 Lichen thallus. Mr. Crombie, one of our ablest Lichenists, 

 vigorously supports his favorite plants in their claim to independ- 

 ence. In maintaining that a lichen is a lichen and nothing else, 

 he speaks of the Fungus- Alga theory (hypothesis) as '* the romance 

 of lichenlogy." He reasons strongly, and seems to prove that the 

 gonidia, though like certain Algae, are not identical with them, and 

 further, that the gonidia really have their birth within the cellules 

 of that part of the plant known as the cortical layer. He deals 

 with several other difficulties that confront the Fungus- Algse theory, 

 but still the new creed gains ground, and is looked upon as the 

 correct thing, for it finds a place in the most recent works of 

 English and other authors. Now, though we cannot settle any 

 knotty questions, we may learn something, by looking at a cross 

 section of a lichen thallus, say a leaf- like one. There are three 

 layers to be seen, namely, a cortical layer (just referred to) of cells 

 with thick walls, then a la}er containing a good proportion of 

 gonidia, and then, underneath, a mass of long thread-like cells 

 (called hyphae) from which false roots (rhizina) proceed. Lichens 

 agree with their allies in not needing true roots, for it is chiefly 

 the attachment they require. The noteworthy point in our section 

 is this — the gonidia do not appear to be in real union with any 

 other portion of the thallus, and but few men have asserted that 

 there ever is such union between them and the so-called Fungus 

 threads (hyphae). Crombie's great point is that such organic con- 

 nection between them and the cortical layer did exist, and was 

 evident enough in the early stages of growth. If he is not accurate 

 here, then the men of the modern theory may have a prima facie 

 case, but they must accept as one of their "articles" something 

 that has no parallel anywhere in nature, and it is this — that tins 

 cells work hard and maintain a great amount of life that " hangs 

 on," not only without being destroyed, but even with great advan- 

 tage to themselves. Crombie tells you that in all ordinary cases 

 a fungus will either wound or slay the plant it lives upon, but the 

 Fungus-Alga men find here a great exception to the rule. Professoy 



