Groom.—Remarks on the Oecology of Coniferae. 247 
point reached by the eosin. As, however, my aim is not to give statistics 
showing the usual rate of ascent of sap, but it is merely to demonstrate that 
water can and does flow rapidly through coniferous wood under the influence 
of transpiration, these deficiencies in observation do not matter. In the 
subjoined tables and calculations I have assumed that the leaves were 
acting and drawing up the eosin for the maximum time in each case, and 
have therefore added a ‘ time-allowance ’ to the time actually intervening 
between the moment of dipping the stem in the eosin and removing it. 
The consequence is that in a number of cases the calculated rate of ascent 
of the eosin solution is certainly less than the true rate. But where this 
calculated rate of ascent seems startlingly great, I have been able to prove 
what was the lowest possible minimum by referring to my notebook and 
noting the moment at which observations on the next succeeding shoot had 
commenced. By this method it is proved, for instance, that in the cases of 
the larch specimens 3, 9, 10, 11, and 14, the lowest possible rates at which 
the eosin ascended were respectively 132, 153, 138, 131, and 126 centimetres 
per hour. The statistics given below, then, must not be regarded as doing 
more than prove that coniferous wood can and does conduct water at a high 
speed , and that in the larch the rate may equal that attained under ide 7 itical 
external circumstances by a very rapidly transpiring dicotyloiis tree , such 
as the beech. In the larch, rates of 204, 240, and 233 cm. per hour were 
attained, while in the fewer beech shoots experimented upon, the highest 
speed calculated was 232. 
The calculated rates of ascent in each of the different species varied 
considerably; for instance, in the case of the larch, between 240 and less 
than 24 cm. per hour. It is probable that the low rates in the larch may 
in some cases have been due to the admission of air into the cut end of the 
stem either at the moment of severance or during transport. In some cases 
the variation in rate could be correlated with change in the surroundings 
or differences in the amount of foliage. For instance, in the first set of 
observations the rates in the cooler, less breezy, less sunny afternoon were 
less in both the larch and beech than in the morning. 
The final table of this series shows the comparative rates of ascent 
of the eosin in different species under identical external factors, as the 
measurements made upon the different shoots within 5-15 minutes of 
one another are recorded on the same horizontal lines of the table. 
After the larch and beech, the Scots pine showed the highest speed of 
flow, namely, 120 cm. per hour, and a minimum of 30 cm. per hour. It 
thus surpassed in the rate of current the deciduous Pseudolarix , whose 
maximum rate was 78 and minimum 28-5. In Abies pectinata the 
maximum rate was 60, and the minimum 35 or 32-5. These results show 
that even an evergreen Conifer can have a relatively rapid flow of water 
through its wood ; but they must not be regarded as demonstrating the 
