NUTRITIVE ORGANS OF CELLULAR PLANTS. 315 



SO as to present more varied forms ; sometimes they are 

 all divided into minute filaments, fonned of cellules in 

 a simple row, and very much resembling the primordial 

 leaves of Phascum. 3d. At the base of the true leaves 

 of the Jungermanniae are often found foliaceous appen- 

 dages, sometimes joined by the side to the leaf, some- 

 times distinct from it. These appendages, which are 

 absent in Mosses and several Hepaticae, have been 

 named Stipules, from a vague analogy to the stipules of 

 Dicotyledons ; they only differ from true leaves in their 

 being smaller, and often disposed in a slightly different 

 manner ; they are, properly speaking, accessory leaves. 



If now we examine those Jungermannias which are 

 nearest allied to Mosses, we shall find some which, 

 analogous to Fissidens, have the leaves disposed in two 

 rows, scarcely, if at all, sheathing, and prolonged by the 

 side upon the stem ; such are Jungermannia sphcero- 

 carpa and /. capitata ; and then the stem, when it does 

 not bear flowers, resembles a petiole furnished with seg- 

 ments. Let us go farther on, and we shall find species 

 where these leaves are united together upon the two 

 sides of the stem, so as to form there a kind of foliaceous 

 limb, sometimes dentated or interrupted when the leaves 

 are incompletely united, and sometimes continuous when 

 they are so completely. 



When this phenomenon takes place in plants provided 

 with stipules, these are found in their usual place, and 

 form kinds of foliaceous scales along the stem, or, to 

 speak according to appearances, along the middle of the 

 leaf, form.ed by the union of the true leaves with the 

 stem : we see this iwJuiigermanniaLyellii. In these difie- 

 rent cases the stem is visible, and represented by the 

 middle of the foliaceous organ, which forms the whole of 

 the plant : sometimes it happens that it is scarcely 

 distinct from the rest of the tissue, and then the plant 



