THE EVOLUTION OF PLANTS 
577 
AiMcesTnAi BRVOPH VTA (HYPOTHETICAL) 
FIG. 410. Hypothetical genealogical tree to illustrate the probable affini- 
ties of the modern plant orders. This diagram is intended to indicate that 
the plant orders now existing are the tips, only, of the branches of a genealog- 
ical tree, whose lower limbs and roots extend into preceding geological 
periods. Our knowledge is not sufficient to enable us to connect these 
branches with each other, nor with the main trunk. The diagram teaches 
that hypothetical (indicated by the dotted line) Anthocerotales gave rise 
to a now fossil Filicalean stock, from which have been derived all the 
modern orders above the mosses and liverworts. 
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