( 411 ) 
that of the plants from the sandy soil is asymmetrical in such a 
way that the top of the seurve lies nearer the minimum. It can not 
be stated with certainty whether in this case we have the same 
phenomenon as with /beris amara, ie. whether the lack of symmetry 
of the curve indicates that it has been shifted to the proximity of 
the lower limit. But the fact that the minimum now obtained, viz. 7, 
is already very small compared with the maximum 41 and that this 
lower limit cannot be zero, renders this view probable. Yet we must 
bear in mind in cases like the present, that the appearance of an 
asymmetrical curve need not in general be a proof that the curve 
is located near one of the limits of the range of variation, but that 
the asymmetry of the curve may also be the consequence of entirely 
different causes. 
Botanical laboratory at Groningen. July 30, 1904. 
EXPLANATION OF THE FIGURES. 
The figures are all reproduced at about half size. In the original figures the 
distances of the intervals, placed along the absciss, are 1 em, each mm. of the 
ordinates having a value of 1°/). So we can find from the length of the ordinates 
the percentage number for each interval. In most figures the ordinates are drawn 
between the two numbers indicating the interval, only in figs. X, XUL and XIV, 
where the observations are not arranged in groups, the ordinates stand above the 
number. The curves of the well-fed plants are drawn in continuous lines, those 
of the badly-fed plants are dotted. 
Fig. I. Iberis amara. Length of the plant from the base of the principal 
stem to the top of the inflorescence of this latter, in cm. 
yall Iberis amara. Length of the leaf, in cm. 
» HL Zberis amara. Number of silicles of the inflorescence of the principal stem. 
» IV. Iberis amara. Number of branches of the second order. 
ores Iberis amara. Number of branches of the third order. 
» VL Anethwm graveolens. Number of umbel-rays. 
» VIL Anethum graveolens. Number of flowers in the umbellet. 
„ VIL. Anethwm graveolens. Number of lobes of the first leaf. 
» IX. Scandix Pecten-Veneris. Number of lobes of the first leaf. 
ATA Xe Scandix Pecten-Veneris. Number of umbel-rays. 
» AL Malva vulgaris. Length of the leaf-blade, in mm. 
» All. Malva vulgaris. Length of the leaf-stalk, in mm. 
» XII. Malva vulgaris. Number of akenes of the schizocarp. 
» XIV. Ranunculus arvensis. Number of fruits per flower. 
» XV. Cardamine hirsuta. Length of the silique, in mm. 
