PRESIDENTIAL ADDRESS. 565 
are represented. For, curiously enough, there does not appear to be any species 
on your Continent of the widely spread genus Equisetum, the only living genus 
of that great phylum of the Equisetales, which figured so largely in the Paleozoic 
Period; and this notwithstanding that one species (H. debile) is present among 
the Polynesian Islands. But all the three other divisions of the Pteridophyta 
are included, and are represented in each case by plants which show peculiar 
and probably for the most part archaic characters. I propose to sketch before 
you very briefly the points of interest which the more notable of these archaic 
types present. Some justification may be found for my doing so because 
nearly all of them have been submitted to detailed study in my laboratory in 
Glasgow, and much of the work has been done upon material supplied to me 
by your own Botanists. I take this opportunity of offering to them collectively 
my hearty thanks. 
The tenure by Dr. Treub of the office of Director of the Botanic Gardens of 
Buitenzorg was rendered famous by his personal investigations, and chiefly by 
his classical researches on the Lycopods. These were followed up by other 
workers, and notably by Bruchmann; so that we now possess a reasonable basis 
for comparison of the different types of the family as regards the prothallus and 
embryology, as well as of the sporophyte plant; and all these characters must be 
brought together as a basis for a sound conclusion as to their phyletic seriation. 
The most peculiar living Lycopods are certainly Zsoétes and Phylloglossum, both 
of which are found in Australia. The former need not be specially discussed 
here, as it is a practically world-wide genus. It must suffice to say that it is 
probably the nearest living thing to the fossils Zepidodendron and Sigillaria, 
and may be described as consisting of an abbreviated and partially differentiated 
Lepidostrobus seated upon a contracted stigmarian base. 
But Phylloglossum, which is peculiar to the Australasian region, naturally 
claims special attention. The plant is well known to botanists as regards its 
external features, its annual storage tuber, its leafy shoot with protophylls and 
roots, and its simple shaft bearing the short strobilus of characteristic Lycopod 
type. But its prothallus has never been properly delineated, though it was 
verbally described by Dr. A. P. W. Thomas in 1901 (Proc. Roy. Soc., vol. 69, 
p- 285). Perhaps the completed statement may have been reserved as a pleasant 
surprise for this Meeting. But the description of thirteen years ago clearly 
shows its similarity to the type of Lycopodium cernuum. The sporophyte com- 
pares rather with Z. inundatum. Both of these are species which, though 
probably not the most primitive of the genus, are far from being the most 
advanced. As all botanists know, the question of the position of Phylloglossum 
chiefly turns upon the view we take of the annual tuber and its protophylls. 
Treub, finding similar conditions in certain embryos of Lycopods, called it a 
‘protocorm,’ and believed that he recognised in it an organ of archaic nature, 
which had played an important part in the early establishment of the sporo- 
phyte in the soil, physiologically independent of the prothallus. I must not 
trouble you here with the whole argument in regard to this view. Facts which 
profoundly affect the conclusion are those showing the inconstancy of occurrence 
of the organ. Mr. Holloway has recently described it as of unusual size in your 
native Z. laterale, as it is also in Z. cernuum. But it is virtually absent in those 
species which have a large intraprothallial foot, such as Z. clavatum, as well as 
in the genus Selaginella and in Isoétes. In DL. Selago, which on other grounds 
appears to be primitive, there is no ‘ protocorm.’ Such facts appear to me 
to indicate caution. They suggest that the ‘ protocorm’ is an opportunist local 
swelling of inconstant occurrence, which, though biologically important in some 
cases, is not really primitive. 
If this is the comparative conclusion, then our view will be that Phylloglossum 
is a type of Lycopod which has assumed, perhaps relatively recently, a very 
practical mode of annual growth. Related, as it appears to be on other points, 
with the Z. inundatum group of species, it has bettered their mode of life. 
ZL. inundatum dies off each year to the very tip of its shoot, so that only the 
bud remains to the following season. It is notable that Goebel has described 
long ago how the young adventitious buds of this species start with small 
‘protocorms,’ quite like those of Phylloglossum itself, or like the embryo of 
L. cernuum. And so we may conclude that in Phylloglossum a tuberous develop- 
ment, containing a store to start the plant in the spring, has been added to what 
