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. Sevei^al 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 

 Cc), 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 Phascu-m showing archegonia (ar), antheridia 

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

 D, after Hofmeister. 



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

 to have medicinal properties: Sphagnum ciispidatum, Oruiuiiia 

 pulvinata; Fmiaria hygromctrica, Fontinalis autipyretica, and sev- 

 eral species of Polytrichuin and Hypnum. 



