124 
Review. 
development of such structures, as judged by their subsequent evo¬ 
lution, is quite insignificant in relation to the plant-body as a whole. 
We cannot so lightly dismiss the instinct of our predecessors, who 
placed “ emergences ” in a morphological category quite distinct 
from leaves and stems. 
(2) . The apparently complete incapacity of any known Bryo- 
phytic sporogonium to produce by enation or otherwise anything in 
the nature of a foliage leaf or sporophyll, though both its spore- 
producing and distributing, and its assimilating mechanisms are 
frequently very highly developed, strongly suggests that the 
elaboration of the sporogonial fruit-body which we actually see 
represents its highest capacity of evolution ; that it does not 
possess the morphological potentialities of an autonomous plant- 
body, and therefore cannot be regarded as the starting point of the 
vascular sporophyte. 
(3) . The branching thallus, on the other hand, as found 
among the Algae and Liverworts, with its unlimited potentialities 
of apical growth, only conditioned by its facilities for the absorption 
and conduction of food, its mixed and often not sharply distin¬ 
guishable dichotomous and monopodial branching, its lateral 
members with their variable specialisation for the assimilating 
function, undoubtedly furnishes a natural and practicable starting 
point for the development of the Vascular plants as we actually see 
them. The fact that the Vascular plant-body is always a sporo¬ 
phyte, while the Thallophyte plant-body has the capacity to produce 
both gametes and spores is, of course, to be correlated with the 
adaptation of the former to terrestrial life. The exact method of 
origin of the Vascular sporophyte from the ancestral Thallophyte 
cannot be determined on the morphological data available, but such 
an origin presents no insuperable theoretical difficulty in the light of 
modern work on the point of occurrence in the life-history of the 
reduction-division. 
Of more special objections to the “ strobiloid theory ” the 
following may be cited :— 
(1) . The “strobiloid theory” requires the microphyllous 
Pteridophytes to be the relatively primitive forms, and the Ferns 
to be derived forms. While it is true that the microphyllous stocks 
are very old, there is no evidence that they are older than the 
Ferns. Further, dichotomous branching of the leaf is found among 
the oldest “microphyllous” forms, except in the case of the 
Lycopods, and suggests that evolution among these stocks has 
been from a larger to a smaller leaf in relation to the size of the 
stem. 
(2) . There is no evidence whatever among the oldest Ferns 
we know of any approach to the microphyllous type. Relative 
microphylly in the Fern-stock and its derivatives is clearly a 
reduction-phenomenon. 
(3) . There is no good evidence of any transition from the 
microphyllous stocks to the Fern-stocks. Lignier’s speculations 
on the Filicinean origin of the Sphenophyllales and Equisetales, if 
they are to be accepted (which the reviewer is not inclined to 
assert), point to an evolutionary transition in a contrary sense. 
The Ophioglossales combine megaphylly with a position of the 
spore-bearing organs characteristic of the microphyllous types, and 
might be regarded as an ascending series from an ancestral micro- 
