JIYCODOMATIA OF THE LEGU.MIN'OSAE. 103 



decay and break-up of the tubercles, reach the soil ready to 

 bring about new infectious. 



The great importance of the tubercles of Leguminosae is 

 that the plants bearing them are capaljle of taking up free 

 nitrogen from the atmosphere and utilizing it, while without 

 the tubercles they could not do so.^ If Leguminosae be grown 

 in soil rich in nitrogenous food-substances, the tubercles are 

 not so well developed. 



According to Schneider,- the host-plant under the influence 

 of the Rhizohium produces cellulose tubes, which become filled 

 with the fungus. According to Beyerink,^ these tubes consist 

 of bacterial slime secreted by the Rhizobium. The epidermal 

 tissue of the tubercles consists of a loose layer of cork with 

 many intercellular spaces ; this arrangement is stated by Frank ^ 

 to facilitate the usual transpiration.' 



•Hellriegel u. Wilfarth, Berickte d. deutsch. hotan. Ge-^., 18S9; also Zdt'<rhrift 

 f. d. liiibeitzucker-Iiulmtrie, 1888. 



-Ber. d. deiUsch. botan. Ges., 1894, p. 11. 



■^ Oentralbl. f. Bacterologie «. Paranitenhmde, 1894. 



* Ber. d. dtutsch. botan. Ges., 1892. 



•' .Schneider {Bulhtin of the Torrey Club, 1892), giv-es a short account of 

 American Rkizobia, and refers to the chief works on this subject. (Edit.) 



