MOSSES. FERNS. 



Ill 



and with expansions or fronds, ordinarily 

 green, analogous to leaves ; the latter often 

 arise from an axis similar to a stem, and 

 sporules are developed upon their external or 

 inferior surface. 



39. In this division we place the mosses, 

 musci, the ferns, felices, and some other 

 families of less importance. 



40. The MOSSES Musci (Jigs. 131 

 and 132) have a very short, herbaceous 

 stem, fixed on the ground, on stones, 



or the bark of trees, by small brown 

 roots, and covered by little leaves 

 in form of scales ; there are no 

 vessels in their interior; finally, 

 their spores are enclosed in lateral 

 or terminal buds, surrounded by 

 a sort of perigon, and arise from 

 the internal parietes of a sort of 

 urn (Jig- 132). "Mosses rank 

 among the smallest of plants ; 



Fig. 131. MOSS. 



Fig. 132. 



MOSS. 



they seldom exceed the height of a few inches ; and many are 

 so minute that they would wholly escape our observation if they 

 did not grow in patches. Several species, indeed, are scarcely 

 visible to the naked eye ; and yet they have a stem, leaves, fruit, 

 and other organs, as the largest plants of the family." Gray's 

 Elements of Botany. 



41. The FERNS Felices (figs. 133 and 134) are 

 herbaceous or arborescent plants, the fronds or leaves 

 of which are alternate, often lobate, and grow upon 

 a sort of vertical stem or rhizome ; we find stomata on 

 the leaves, and trachea? and other vessels in their 

 petioles. Their organs of fructification are found on 

 the inferior surface, of the leaves, towards the edge, at 

 the extremity of the veins (fig. 133). "Although 

 the ferns of the United States and of all northern cli- 

 mates have prostrate stems, and consequently do not 



Fig. 133. 



FERN. 



Explanation of Fig. 132. A magnified view of the capsule of a moss, 

 enclosing the sporules. The sporule case, or theca, also called capsule, 

 is a little oblong urn-shaped body, which in a few cases is sessile, but 

 is usually borne on a filiform fruit stalk or seta (Jig. 131). The tall 

 cap-like part of the figure above, somewhat like an extinguisher, is called 

 a caly'ptra, and when of this form is said to be mitriform. 



39. What families belong to the semi- vascular plants? 



40. What are the general characters of the mosses ? 



41. What are the general characters of the ferns ? 



