Nov. 1897.] BOTANICAL SOCIETY OF EDINBUKGH 81 



observable only dnriug the latter part of its growth, when 

 its seed is forming. 



As I have already observed, leguminous plants can grow 

 to maturity quite well without the possession of nodules, so 

 long as the nitrogenous matter they require for their growth 

 can be obtained easily from the soil. Plants grown in 

 a sterilised soil and supplied with nitrates, as well as the 

 other plant food required, grow to perfection, and in a 

 natural unsterilised soil, rich in plant food, where tlie 

 assistance of nodules to enable the plants to obtain nitrogen 

 from the air is unnecessary, they may have their roots 

 abundantly studded with nodules. Frank describes an 

 experiment with Pliascohis vulgaris grown in a poor sandy 

 soil containing only about '01 per cent, of nitrogen, where 

 the plants grown in sterilised pots and unsterilised pots, with 

 inoculated and uninoculated, grew in very much the same 

 way, and that very poorly ; and when grown in a soil rich 

 with nitrogenous organic matter the beans grew exceedingly 

 well, but quite indifferently as to whether it had been 

 previously sterilised or not, or whether it had been in- 

 oculated or not. He came to the conclusion that Phaseolus 

 behaved toward the RMzoMum as if it M'ere a non-leguminous 

 plant, but that, you may remember, was the plant within 

 whose cotyledons he succeeded in tracing the presence of 

 bacteroids, 



A very instructive series of experiments was carried out 

 by Dr. Stocklasa in 1894, with the view of ascertaining 

 whether there was any necessary connection between 

 nodule formation and the formation of nitrogenous tissue 

 in leguminous plants, and he chose for his subject of 

 experiment Lupinus angustifolius, which he grew upon a 

 light sandy loam, poor in nitrogen, in the open field. 



He selected, while in bloom, ten well-grown plants with 

 nodules on their roots, and ten others of similar growth 

 without nodules. The two sets of plants were as equal in 

 every way as could be wished, having twenty-three and 

 twenty-two leaves per plant respectively. These he analysed, 

 and found that there was practically no difference in the 

 amount of nitrogen they contained. The only difference 

 noticed was that the nitrogen was somewhat unequally 

 distributed. The plants with nodules had rather more 



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