PRINCIPAL GROUPS OF PLANTS. 85 



nature of tannin, resins, ethereal oils, glucosides, alkaloids, color- 

 ing compounds, and organic acids like citric, oxalic, tartaric, and 

 aconitic. In the mosses starch and silicon salts are found in 

 addition. Several species of Marchantia and Jungermannia are 



FIG. 49. Longitudinal sections through tips of leafy branches of mosses. A, show- 

 ing antheridia (a, b) in different stages of development and paraphyses or cell-threads 

 (c), the apical cell of which is spherical and contains chlorophyll, and leaves (d, e); B, show- 

 ing archegonia (a) and leaves (b) ; C, section of Bryum showing both archegonia, and an- 

 theridia, paraphyses, and leaves; D, section of Phascum showing archegonia (ar), antheridia 

 (an), thread-like paraphyses (p), and leaves (b). A, and B, after Sachs; C, after Limpricht; 

 D, after Hofmeister. 



used in medicine. Of the mosses the following have been found 

 to have medicinal properties : Sphagnum cuspidatum, Grimtnia 

 pulvinata, Funaria hygrometrica, Fontinalis antipyretica, and sev- 

 eral species of Polytrichum and Hypnum. 



