The Effect of Late Frost on the Wood of 
Acer Pseudoplatanus, Linn. 
BY 
JAMES TEMPLETON, B.Sc. 
Senior Botanist, Department of Agriculture, Cairo. 
With Plates CXCI-CXCIII. 
In the course of an investigation of the moisture content of 
the wood of Acer Pseudoplatanus, Linn., a tree was felled in 
the Royal Botanic Garden, Edinburgh, in March of 1921. 
Transverse cuts were taken from the bole and crown at 
measured heights above ground level. A superficial examination 
revealed the fact that one wood-ring of the lowest cut stood out 
conspicuously from all the others because of a narrow zone at its 
inner margin being much lighter in colour than the rest of the 
wood (Pl. CXCI, Fig. 1a). On the cut surface of the stump, the 
ring was also very well marked ; but 180 cms. above ground level 
it was in no way different from the normal. A closer examina- 
tion of this phenomenon gave results which, though in no way 
connected with the original line of research, appear to be worthy 
of record. 
The annual ring referred to was apparently laid down in the 
year 1897. On examining transverse and longitudinal sections 
of it microscopically it became evident that the cambium, from 
the commencement of its activity in the spring of that year, and 
for some time later, had acted in a manner far from normal. In 
Plate CXCII, Fig. 1 shows a transverse section of two consecutive 
typical annual rings of Acer: Fig. 2., of the rings laid down in 
1896 (a) and 1897 (b). In Fig. 1, it will be observed that the 
medullary rays run continuously through the adjacent rings; 
but in Fig. 2 this is not the case, for the cambium, instead of 
giving rise to tracheides, vasa, and medullary ray cells, has laid 
down at the commencement of its activity for the year, several 
layers of parenchymatous cells with rather thick, lignified walls. 
A transition from these to normal wood elements—formed later in 
Notes, R.B.G., Edin., No. LXVI, January 1923.] 
