Note 9 — Chapter III · THE MORPHOLOGICAL COMPOSITION OF PLANTS, CONTINUED.

To this interpretation it is objected that “the more-developed Jungermanniaceæ” do not appear to have arisen from the lower forms of Jungermanniaceæ—that is to say, from such lower forms as are now existing. It may, however, be contended that this fact does not exclude the interpretation given; since the higher forms may well have been evolved, not from any of the lower forms we now know, but from lower forms which have become extinct. This, indeed, is the implication of the evolutionary process as pointed out in the note to Chap. I. If then we assume some early type of intermediate structure, the explanation may not improbably hold.