Dutt. —Pityostrobus macrocephalus, L. and H. 535 
matter. The cortical region consists of thick-walled cells circular in outline. 
It is marked by the presence of large, regularly disposed resin-Canals 
arranged in a circle round the vascular cylinder; The canals are very large 
in the case of P . ovatus • in the Sedgwick Museum cone they are slightly 
smaller and less uniform. In all the transverse sections of P. ovatus the 
canals are exactly thirteen in number. The transverse section prepared 
from the Sedgwick Museum cone of P. macrocephalus is unfortunately not 
complete, but about three-quarters of the axis is present and is provided 
with nine resin-canals, so that, in this case also, the total number was probably 
thirteen. 
Although such a strikingly large and regular set of canals is not to be 
found, as far as I am aware, in any other recent or fossil Conifer, a series of 
canals, varying in diameter and disposition, is of frequent occurrence in the 
cone-axes of many existing Abietineae. Moreover, Radais ( 12 ) has shown 
that in recent species the number of canals may be similarly constant, and 
represents the number of orthostichies 5 for the canals run vertically 
between the ofthostichies, giving off branches which accompany the 
sporophyll traces. The latter, the ‘ canaux appendiculailes ’ of Radais, 
can be well seen in the transverse sections of these cones (Fig. 6, PI. XV). 
Since we have thus every justification for assuming that the case here is 
exactly as in the recent species, we may conclude that the denominator of 
the phyllotaxis fraction is thirteen, and this number fits in with the ordinary 
Fibonacci series. Henslow made a diagram of the phyllotaxis of his 
specimen of P. macrocephalus , and concluded that the arrangement was 
represented by the fraction -||. Carfuthers rightly points out that this is an 
anomalous arrangement, but from his examination of Mr; Dowker’s specimen 
of P. macrocephalus he determined the ratio as §. From the considerations 
given above it is probable that the real value in both cones must be the next 
in the series, viz. x 2 * * 5 3. 
2. The Bract Scales. 
Neither Carruthers nor any of the later writers makes any mention of 
the bract-scales. Yet evidence on this point is not lacking. In longitudinal 
sections of P. macrocephalus the bract-scale could sometimes be identified 
as a stout, pointed body inserted below the ovuliferous scale and occupying 
the space just above the micropyle of the ovule below. A similar structure 
was noted in a longitudinal section from the base of the cone of P . ovatus. 
A transverse section of such a scale can be seen in the tangential section 
from the same cone (see Fig. 4, PI. XV). This is composed of compact, thick- 
walled tissue and possesses a row of small resin canals but no vascular 
bundle. In no case has it been possible to make any observations on the 
vascular supply of the bract -scale. 
O o 2 
