Igt5] AASE—M EGASPOROPHYLLS OF CONIFERS 299 
vegetative leaf. This is a characteristic which so far as investi- 
gated occurs outside the Araucarineae only in Podocarpus Nageia. 
The sporophyll of Araucaria is characterized by the so-called 
ligule, which there is good reason to believe is homologous with 
the scale described in the foregoing groups. In the young strobilus 
of Araucaria Rulei and Araucaria Balansi the comparatively small 
ligule is attached to the bract at its base only, the greater portion 
being free. In the older strobilus it is free only at the tip. Distal 
to the line of coalescence of bract and scale the bract remains thick 
and wide, then becomes narrow and stiff, resembling the bracts 
at the base of the strobilus. 
The vascular supply to the sporophyll of A. Balansi (figs. 
142-154) arises as a single bundle near the base of the gap in the 
strobilus cylinder. In the middle of the cortex the single bundle 
divides into two unequal parts, the smaller of which twists through 
an angle of 180° so as to lie above the parent bundle with its xylem 
facing the xylem of the latter. The upper bundle may or may not 
divide at this stage; the lower bundle divides into two or three; in 
case of two, one bundle soon divides and a median lower bundle 
isformed. The lateral bundles divide actively; some of the result- 
ing bundles become inverted and lie on a level with the upper 
bundle, others normally oriented come to lie on a level with the 
lower median bundle. Where the sporophyll broadens, branches 
with normal orientation enter the wings. Behind the ovules the 
bundles of the upper series begin to converge in groups, and finally 
end in masses of irregular tracheids. A bundle is sometimes found 
to continue almost to the free portion of the ligule. Where the 
bract becomes narrow, the lower bundles also end, with the excep- 
tion of about three median ones which extend into the slender 
portion. In the lowest sporophylls, where the ovule and scale are 
poorly developed or absent, the upper bundles are weak and few 
in number, or wanting. 
In the other forms investigated, A. Rulei (figs. 155-161) and 
A. excelsa, the general features are as in the above-described species. 
The strobilus of Agathis australis (figs. 162-170) is composed of 
numerous sporophylls which are very closely packed, probably 
owing to the shortening of the strobilus axis. A ligule, as found in 
