266 Annual Report, for 1906 of the Consulting Botanist . 
Dr. Ritter von WEINZIERL, of Vienna, referred to 
modified Austrian methods of testing sugar beet and mangel 
wurzel seed. These methods depend upon the number of 
seeds that germinate in a certain weight (15 grains) within 
six to twelve days, and the calculation is as follows : — 100 x 
the number of seeds that have germinated in that quantity, 
divided by the number of fruits contained therein. 1 
Dr. RODEWALD, of Kiel, referred to the difficulty of deter- 
mining the purity of seeds, especially in the finer grass seeds. 
Generally speaking, the purity of a seed depends upon the 
absence of all inert matter, weeds, injured or broken seeds of 
the kind examined, &c. About 200 or 400 seeds from which 
the impurities have been removed are taken to determine the 
percentage of germination. Dr. Rodewald pointed out the 
greater utility of the purity test of the finer grasses by weight. 
Everything that is not true to name of the kind of seed 
examined is counted as an impurity, and of the true seeds 
a certain weighed portion is taken for germination. In this 
way the great difficulty is overcome, which arises from dis- 
tinguishing between a glume containing a germinable seed 
and a glume without one. Other members of the conference 
suggested reflected light as a better method of determining 
whether a glume carries a seed or not. 
Dr. von Degen, of Budapest, dealt with dodder in clovers. 
He suggested that dodder should be made a subject for 
international legislation, although this might prove difficult. 
In dealing with the larger kinds of dodder as found in 
seeds imported from Hungary and Chili (see page 256) it is 
important to determine the countries of Europe in which 
these dodders will grow and ripen their seeds, as it has been 
stated that dodder from these sources does not ripen its 
seeds in the northern countries of Europe, like Norway, 
Ireland, and Scotland, but that in southern England 2 and 
Sweden the seeds have been known to ripen. 
Dr. Appel, of Dahlem, spoke on the relation of plant 
diseases to the seed examination, and pointed out the necessity 
for determining the presence of the micro-organisms of disease 
in the samples of seeds under examination. 
Dr. HlLTNER, of Munich, raised the question of germination, 
speaking on the influence of the quality of water, the kind and 
1 The “seed” of mangels or sugar beet sold commercially as such is botani- 
cally the fruit, which contains from 1 to 5 true seeds. Supposing 60 fruits 
weigh 15 grains and 75 seeds have germinated, the percentage is found by 
multiplying 75 by 100, which equals 7,500, and dividing it by the number of 
fruits, i.e., 60, and the percentage found is 125. This indicates that 100 fruits 
produce 125 seedlings. 
2 I am not aware that dodder from Hungary or Chili has ever been known 
to ripen its seeds in any part of the British Isles. 
