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PKOFESSOK K. PEARSOX AXL) OTHERS OX 
It will be remarked at once that the leaves with an even number of leaflets are 
relatively infrequent; there is usually a single leaflet at the end of the compound 
leaf. I was able at Hampden, however, to obtain leaves illustrating almost the 
whole evolution of this single leaflet. Sometimes this leaflet had the slightest 
division at its point ; this division was found in most stages of double tongued 
leaflet down to a complete double leaf, which would be reckoned as two piniiGE. In 
the same way the centre leaflet was found slightly trisected, three tongued and 
finally a triple leaflet scarcely distinguishable from the usual single leaf at the end 
and the two nearest side leaflets. Very occasionally the double leaflet seemed to 
give one side leaflet and the final leaflet. Of course, all these anomalies were rare 
and had to be sought for, but they would form in themselves a suggestive study. 
The Dorsetshire series gives 9 instead of 11 as the mode, and 7 are more 
frec[uent than 13. This latter result is also true for the Monmouthshire series, 
which again has nothing like the same preponderance on its modal 11 as the 
Buckinghamsliire series. I take it that the greater variability of both Dorsetshire 
and Monmouthshire series, together with their greater relative proportion of com¬ 
pound leaves with 9 and 7 pinnw, is due to tliose series containing a much larger 
proportion than the Buckinghamshire series of small trees. 
For ashes in general, I think, we may safely take 10 as the average (but not 
the modal) number of pinnw, the standard deviation is D9 pinnce, and the leaf 
resemblance is measured by a correlatiorr of '4. 
If we conrpare racial and irrdlvidrral variabilities we have ; 
Series. 
S. I). 
S. I), of array. 
Coefficient of 
variation. 
Percentage 
variability. | 
Buckinghamshire . 
1-6891 
1-5663 
15-46 
92-73 
Dorsetshire .... 
1-9759 
1-8140 
18-65 
91-81 
Monmouthshire 
2 - 0058 
1-8342 
18-57 
91-44 
Mean . . . 
1-8903 
1-7382 
17-56 
91-99 1 
Thrrs 92 per cent, of tire total racial varialrility of tlris character of the ash is to be 
fourrd in the individrral tree, aird here, as iir all our other series, it is irrrpossible to 
assert that variation is a result of sexrral reprudirctiorr ; it is clearly arr esserrtial 
factor of the irrdlvidrral growth. I c(rnclirde with the actrral tables of data for the 
three series. 
