Note 8 — Chapter III · THE MORPHOLOGICAL COMPOSITION OF PLANTS, CONTINUED.

Schleiden, who chooses to regard as an axis that which Mr. Berkeley, with more obvious truth, calls a mid-rib, says:—“The flat stem of the Liverworts presents many varieties, consisting frequently of one simple layer of thin-walled cells, or it exhibits in its axis the elements of the ordinary stem.” This passage exemplifies the wholly gratuitous hypotheses which men will sometimes espouse, to escape hypotheses they dislike. Schleiden, with the positiveness characteristic of him, asserts the primordial distinction between axial organs and foliar organs. In the higher Archegoniates he sees an undeniable stem. In the lower Archegoniates, clearly allied to them by their fructification, there is no structure having the remotest resemblance to a stem. But to save his hypothesis, Schleiden calls that “a flat stem,” which is obviously a structure in which stem and leaf are not differentiated. He is the more to be blamed for this unphilosophical assumption, since he is merciless in his strictures on the unphilosophical assumptions of other botanists.