E antes . — The Morphology of Agathis australis . 23 
is also the result of similar fusion, as Mr. Sinnott is clearly demonstrating in 
the above-mentioned paper— a complete series existing from forms of Podo- 
carpus with free bract and scale to the AgathisAike cone scales of Saxe- 
gothaea and of Microcachrys . Too little comparative work has been done 
on the cone scales of the many genera of the Conifers. On looking over the 
entire field, the conditions obtaining in the different tribes cannot be inter- 
preted otherwise than as indicating the origin of the araucarian condition. 
Leaving the discussion of the Podocarpineae to Mr. Sinnott, the Taxodineae 
give us Cunninghamia , with sporophylls closely similar to those of Agathis, 
and Athrotaxis , not only with the species A. selaginoides , D. Don., having 
cone scales internally as well as externally the counterpart of those of 
Agathis, but demonstrating in its other species the origin of such a very 
reduced scale. A. cupressoides, D. Don., has dominant scale and weak bract ; 
A. laxifolia , Hook., scale and bract of nearly equal prominence. 
The genus Araucaria itself must be considered in detail. Its cone 
scales possess a ventral structure, the ligule,in contrast with those of Agathis, 
which have no outgrowths on the apparently very simple scale. By those 
who consider the araucarian cone scale to be of double origin, the ligule 
is generally believed to be the remnant of the fertile scale ; by others it is 
supposed to be merely a ventral outgrowth of the sporophyll. This ligule 
is found in all species of the genus, but in varying degrees of development 
— from the stout, prominent structure of A. Bidzvillii , Hook., to the thin, 
almost indistinguishable projection in A. brasiliana , A. Rich. The vascular 
supply of the cone-scales varies in like proportion. The anatomy of these 
structures divides the genus into three distinct groups which show stages in 
reduction from the abietineous type of vascular supply to that of Agathis. 
Groiip I. The vascular supply originates as two entirely separate 
strands which, though later brought close together and somewhat interlaced 
below the huge embedded ovule, maintain their independence. The upper 
forms an inverted series supplying the ovule and the ligule, and the lower 
a strong bracteal series. 
Group II. The vascular supply arises as a single strand, which imme- 
diately divides to form two opposed bundles. The upper supplies the ovule 
and the ligule (whenever the latter has a supply) ; and the lower, the bract 
as usual. 
Group III. The vascular supply arises as in Group II, but does not 
divide to form two opposed series, its behaviour being exactly that of the 
lower primary bundle of Groups I and II. 
These three groups, as defined by differences of anatomical structure, 
correspond in part to the systematic subdivisions of the genus. The section 
Eutacta, so far as its members have been studied, forms Group II, and 
Groups I and III fall into the section Colymbea. The latter section thus 
contains the most primitive and the most specialized forms. The geo- 
