248 PLANT AND ORGANIC CHEMISTRY 



importance. In all cases of distinct characteristic habits of 

 reproduction and form, one or more different chemical com- 

 pounds is found. 



In the next group of the Musiceae, or mosses, is an absence of 

 some chemical compounds that were characteristic of the classes 

 just described. Many of the albuminous substances are pre- 

 sent. Starch 1 is found, often in large quantities, and also oily 

 fats, which are contained in the oil bodies of the liverworts; 

 wa!x, 2 organic acids, including aconitic acid, and tannin, which 

 is found for the first time at this evolutionary stage of the plant 

 kingdom. 



The vascular Cryptogams are especially characterized by 

 their mineral composition. 3 The ash is extraordinarily rich 

 in silicic acid and alumina. 



Equisetum 4 silicic acid 60 per cent. 



Aspidium " " 13 " " 



Asplenium " " 35 " " 



Osmunda " " 53 " " 



Lycopodium 5 " " 14 " " 



alumina 261027 " " 



manganese 2102.5 " " 



These various plants contain acids and compounds peculiar 

 to themselves. 



As we ascend in the plant scale, we reach the Phanerogams. 

 These plants are characterized by the production of true seeds, 

 and many chemical compounds not found in lower plants. 



It will be convenient, in speaking of these higher groups, 

 to follow M. Heckel's 6 scheme of plant evolution. All these 

 plants are grouped upder three main divisions: apetalous, 

 monocotyledonous, and dicotyledonous, and these main di- 

 visions are further subdivided. 



It will be observed that these three main parallel columns 

 are divided into three general horizontal planes. 



1 E. Treffner, Inaugur. Diss. Dorpat, 1880. 2 W. Pfeffer, Flora, 1874. 



3 Die Pftanzenstoffe, p. 323. W. Lange, Bui. Bcr., xi, 822. 



4 Ann. Chim. Phys., xli, 62, 208; Ann. Chim. Pharm., Ixxvii, 295. 



5 Fliickiger, Pharmakognosie. Kamp, Ann. Chim. Pharm., c, 300. 



6 Revue Scientifique, March 13, 1886. 



