230 



BOTANY 



PAKT I 



and the following genera of the Ehinanthacea, Pihinanthu.% Euphrasia 

 PecUcularis, Bartsia, and Tozzia may be mentioned as examples of 

 plants showing these peculiar conditions. In Tozda the parasitism is 

 well marked in the earliest developmental stages. The Mistletoe 

 (Fiscuin album), although 

 strictly parasitic, pos- 

 sesses, like many of the 

 allied foreign genera of 

 the Loranthaceae, fairly 

 large leaves well supplied 



K 







Fio. 201.— A root of Vicia Faha, 

 with numerous root - tubercles. 

 (Reduced.) 



Pig. 202. — 1, Youug tubercles (K) on a root (W) of Vicia Faba 

 B, large-celled tissue filled with masses of Bacteria, M, the 

 "meristem" of this. T, tracheides. (x 60.) 2, A cell of 

 the tubercle filled with thousands of Bacteria, and beside 

 it some un-infected cells, (x 320.) 3, An infected root- 

 hair containing the " infection hypha." (x 320.) /4, Bacteri- 

 oids. ;>, Unaltered Bacilli, (x 1200.) 



with chlorophyll, and quite able to provide all the carbohydrates re- 

 quired. By its reduced root system it obtains, however, from the 

 host-plant (as Heinricher has also shown to be probable in the 

 case of the Rhinanthaceae) its supply of water and dissolved salts. 



In contrast to these plants, which are either demonstrably or probably 

 supplied with organically combined nitrogen, there are certain micro- 



