FLOWER-STALK ОЕ THE HYACINTH. 143 
Starting from the measurement at 10 р.м. on Feb. 27th, the lowest of the three 
zones, which then measured 0:1 in., had increased by March 13th so as to make up the 
two zones C & D together 4:25 in., or 4150 per cent. of its original length, while the 
remainder had only increased from 1:0 to 3:95, or at the rate of 295 per cent. Again, 
starting from 10 р.м. on March 29th, when the four zones were first marked off, the 
ultimate increase of the lowest was from 0:2 to 2:75 in., ог 1275 per cent.; the next 
greatest energy was displayed by the uppermost, which increased from 0°55 to 9:2, or 
just 300 per cent. ; next came the second zone from the top, which showed an increase 
from 0:5 to 1-75, or 250 per cent. ; and finally the third from the top, showing an increase 
from 0°5 to 155 in., or exactly 200 per cent. The curve B in the accompanying diagram 
(p. 141) illustrates the total energy of growth of Section D as compared with that of Sec- 
tions A, B, and С taken together, the former being, as in the case of the previous curve, 
in excess during almost the whole period of growth. The rate of growth was again 
subjeet to great irregularities, which will be seen to correspond to a considerable extent 
to those of curve A, and were no doubt attributable mainly to changes in temperature. 
Making the division between day and night as before at 10 А.М. and 10 r.m., the total 
amount of growth was again not very different in the two; but instead of being, as in 
the previous case, slightly in favour of the day, was rather more decidedly in favour of 
the night; of the 6:5 in. growth from Feb. 29th to March 13th, 3 inches was by day, 
and 3:5 inches by night. 
It will therefore be seen that, as far as these observations on the relative growth of 
different portions of the same internode go, they are entirely in accord with the statement 
of Prof. Sachs (vide ante, p. 135), in regard to that of different internodes on the same 
branch, that the maximum energy of growth is exhibited at a period considerably below 
the punctum vegetationis, though it is here much nearer the base than in the cases 
measured by Sachs. "This brings out into still stronger relief the opposite phenomenon 
displayed by the elongated submerged flower-stalk of Vallisneria, the energy of growth 
of which is manifested mainly in the apical portion. Тһе elongation of the peduncle 
of the Hyacinth continues considerably after the complete expansion of the flowers, until 
the lowest in the raceme begin to fade. 
These observations differ in several points from those on the flower-stalk of the 
Hyacinth recorded by Münter in the * Botanische Zeitung ' for 1843, Feb. 24; but as he 
gives no measurements, I cannot think that these latter are of very great weight. Не 
deseribes its growth as not centrifugal, like that of most flower-stalks, but centripetal ; 
that is, it сеазез to grow first near the flower and finally at the base. It will be seen that 
шу two experiments (and I think the care with which the measurements were made 
precludes any possibility of mistake) agree in this, that while the energy of growth is 
Sreatest in the basal portion, the apical portion continues to grow for very nearly or 
quiteas long. Тһе growth of the flower-stalk of Pelargoniwm he describes, on the other 
hand, as centrifugal, the growth of each zone ceasing before the one next above it. 
With regard to the relative amount of growth by day and by night, Münter also gives 
по measurements, but states that in the daytime the plant grows at first five times, then 
four times, and then three times stronger than by night. This differs materially from 
SECOND SERIES.— BOTANY, VOL. I. E 
