300 
PEOFESSOE K. PEAESON AND OTHEES ON 
(8.) B. Spcmish Chestnut (Castanea vulgaris). Veins in the Leaf. —A character which 
at first sight appears easy to determine is the number of veins running from the main 
rib to the edge of a leaf Tlie leaves of many trees, however, will on examination 
be found quite unsuitable, the veining being far too complex, too much indeed of a 
network. Among fairly practicable leaves are those of the beech and the SjDanish 
chestnut. Here two fundamental difficulties occur : (i.) near the tip of the leaf the 
num]3er of veins becomes rather difficult to register. In the case of the beech bv 
holding the leaf in various lights or even using a lens, it was possible to be fairlv 
sure of the separate veins. In the case of the chestnut, the total number of veins is 
so great that the addition or omission of a single vein is hardly likely on the average 
to lead to any serious error, (ii.) The occasional branching or bifurcation of the vein 
formed a difficulty, especially if it occurred near the edge of the leaf If the bifurca¬ 
tion occurred close up to the main rib of the leaf, the vein system was counted as 
two ; if close to the edge of the leaf as one; intermediate bifurcations had to be 
left to the judgment of the recorder, having regard to the general ajDpearance of the 
leaf and its system of subsidiary veining. The doubtful cases were not very many, 
and occurred more frequently with the chestnut than with the beech leaves. In 
neither case was the main rib or vein included in the total number for the leaf, 
the record was of the side veins flowing from this. The numbers right and left 
in the l^eech leaf were found to be far more nearly equal than in the case of the 
chestnut, which thus possessed considerably greater asymmetry. In these cases 
as in those of the ash, the leaves were gathered at random round the tree, and 
at random on the branches, care being, however, taken in the case of the chestnut 
to avoid leaves in the neighbomliood of the fruit. 
Series (i.). Hampden Spanish Chestnuts. 
I had hoped to get records for 26 leaves from each of 100 trees from the splendid 
chestnut avenue at Hampden House, ’but it provided records for some 60 trees only. 
These I owe to Miss Lina Eckenstein. I was able to add by diligent search 
al)out 25 additional trees from the same neighbourhood. AU these were large 
forest trees of splendid growth. In order to make the number up to 100, some 15 
additional trees were added, these being all large old trees from other neighbour¬ 
hoods. I look iqion this series as a fairly homogeneous one, representing the degree 
of resemblance between leaves on fully developed forest trees. The counting of the 
veins on this series was undertaken by Miss C. D. Fawcett, B.Sc., and the 
tabulating and numerical reduction by Dr. Lee. Both these processes involved 
an immense amount of labour, in fact days and days of careful and fatiguing work. 
* The leaves were all gathered in the autumn, towards the fall. 
