iooo Groom .— The Evolution of the Annual Ring and 
each ray becomes divided up by fibres into superposed c partial ’ rays, and 
this division becomes more extensive outwards because the partitions formed 
by the fibres become more numerous and thicker. Thus, according to 
L. Jost, the condition as regards division of the rays is exactly the 
reverse of that described later by Eames and Bailey in connexion with 
the seedlings of Quercus and Alnus. It seemed possible that in seedlings 
of Fagus the relation of the rays might be as in Quercus according to 
Eames. Accordingly, R. Tabor 1 investigated the matter and found that 
even in the seedling stem of Fagus sylvatica , the large primary rays, when 
traced outwards, undergo division in the manner described by Jost. Thus, 
on the hypothesis that the seedling is the seat of primitive characters, 
Fagus and Quercus point in opposite directions. But Tabor’s preliminary 
observations strongly suggest that in the seedling of Fagus, secondary 
rays do become gradually linked up and give way farther outwards to 
broad rays. Such a fact, if established, that side by side in the same 
annual rings disintegration and integration are taking place in the rays, 
would point to the processes as being determined by physiological needs, 
not by phylogenetic characters. 
The Indian oak, Q. (Pasania ) fenestrata , 2 is of interest in relation 
to the problem under discussion, and appears to suggest strongly that, at 
least in some cases, the bundles of narrow rays have been produced phyio- 
genetically by disintegration of broad rays. The material I examined was 
a trunk whose diameter was twenty-eight centimetres. It possesses thin 
rays several cells in thickness, which are characterized by their dispro¬ 
portionate height (PI. LXXVI, Fig. 32) ; or in other words the height 
corresponds to rays very much broader than these. Now in many (most?) 
species of Quercus the boundary of the annual ring dips in where it crosses 
a broad ray, and the extent of the inward bend is at least often proportional 
to the width of the ray. In Q. fenestrata these characteristic high rays are 
often approximated in pairs, and between the two rays forming a pair, the 
boundary of the annual ring is much nearer the centre of the stem than it is 
elsewhere (PI. LXXV, Fig. 12). Moreover, the space between the two rays 
forming a pair is devoid of vessels. These three sets of facts denote that 
in some way the pair of high rays, together with the tissue between them, is 
equivalent to a single broad ray; and the very considerable inward dip of 
the annual ring between the two rays finds simplest explanation in the 
assumption that in the ancestor this complex was represented solely by 
ray tissue. This case of Q. fenestrata , while clearly suggesting that dis¬ 
integration of the broad rays into narrow rays can take place, is not 
1 Mr. Tabor’s work is as yet incomplete and unpublished. 
2 The specimen from India arrived labelled Q. spicata, but the Herbarium specimen presumably 
obtained from the same individual tree was determined at Kew to be Q. fenestrata. Yet the 
structure of the wood does not agree with Gamble’s description of that of Q. fenestrata , and 
•Mr. Gamble suggests that my specimen may be the wood of Q. ( Pasania ) lanceaefolia. 
