nOMOTYPOSIS IX THE VEGETABLE KINGDOM. 
3;i3 
It will be seen at once that while in the case of ceterach the variability has fallen to 
less than half that of the hartstongne—being close to that of the Nigella Ilispanica 
and less than that of holly—still the measure of the indivnduality, i.e., the degree of 
sameness in like organs, is to the limit of accuracy defined by its probable error 
identical with that of hartstongne. Considering the difficulties arising from environ¬ 
ment, difference of age, and from standards of reckoning, this agreement is remarkable. 
It seems to me that the basis of the identity, the bulk of the agreement, must have 
other sources than a balance between the resemblances produced in undifferentiated 
like organs by such diverse causes as environment on the one hand and age on the 
other acting upon the individual plants. I hope that further investigations upon 
ferns may be forthcoming. Table XIX. contains tlie classified data for ceterach. 
Section V. — Onions (Allium cepa). Great Hampden. 
(19.) The veins in the successive tunics of onions occurred to me as a possible 
character for computation, no differentiation of the number of veins with the 
position of the tunic being discoverable. The number of tunics on which the veins 
were countable was aliout six, but the process of counting itself was for more than 
one reason a most trying one. As there were so few “ like organs ” to each individual, 
it was needful to deal with at least 200. I accordingly purchased about 250 English 
onions; these were in three groups, and came from as many cottage gardens. Their 
average horizontal diameter was about 2 inches, and they appeared very uniform in 
character. It is quite possilile, however, that there may he some heterogeneity 
introduced into the series by this mixture of onions from different sources, but I did 
not at the time see my Avay to obtaining the whole series from one homogeneous 
sowing."^ The entire work of counting and calculating on 200 of these onions was 
most valiantly undertaken by Dr. Lee.! Each onion was cut through horizontally ; 
the tunics then came easily apart, and these were held up to the light, and the 
number of veins, ranging from 18 to 54, then counted and recorded. The following 
table contains the chief numerical constants :— 
* The onions were purchased at an auction following a harvest festival; the great bulk of them had 
formed a large chancel crucifix constructed of two dillerent species from one cottage garden. The 
English onions from this crucifix formed a most homogeneous group, having l)eeir already selected for 
uniformity of size and appearance. I supplemented these by the purchase of two other smaller 
“ offerings,” closely resembling them. 
t If any of my readers wish to appreciate the purely plajskal difficulties of the task, they should try 
the effect of slicing and counting four or five onions, and they will, I think, be inclined, as I soon was, to 
give up the task in despair. 
