7o 



PROCEEDINGS OF THE 



might be separately considered. They are aliiidst certainly con- 

 nected witli the Cordaitales, and indeed more cJosely than the 

 true Coniferai. The Maidenhair trees are not, however, of much 

 consequence for our immediate purpose, for they cannot really be 

 called a higher group than the Cordaitales, but are merely slight 

 moditications of an old and persistent type. 



We now come to the Angiosperms. Until quite recently 

 no serious hypothesis as to their origin has heen in the field, 

 for comparisons with Isoetes as regards some anatomical points, 

 or with Sela<j'niella as regards the endosperm, were obviously the 

 merest analogies at the best. There was a vague idea in the air 

 that their origin may have been obscure, from small, unimportant 

 plants, easily overlooked or not preserved : so that they migiit have 

 existed for a long time as inconspicuous members of tlie flora, side 

 by side with the dominant Cycadophyta and Conifers. 1 think 

 this was the current idea uutil Wieland, and his apostles Arber 

 and Parkin, showed how we might well have had the ancestors of 

 Angiosperms (or something like them) in our hands all the time 

 without knowing it — that is, they showed that the Mesozoie 

 Cycadophytes themselves, more than any other group, betray 

 affinity with the great x'ace which succeeded them. This im- 

 portant conception was suggested by the discovery that the 

 fructifications of Bennettitea\ the characteristic Mesozoie Cvca- 

 dophytes, were organized essentially like the bisexual flowers of 

 an Angiosperm, though, of course, with important differences 

 in detail. The latest work has further strengthened the com- 

 parison, and there are strong grounds for the hypothesis that 

 the Angiosperms arose from a stock nearly allied to such 

 Mesozoie Cycadophyta as the Bennettiteae. The view is by no 

 means universally accepted : some botanists, as, for example. 

 Miss IStopes and Prof. Fiijii in their recent work on the Cretaceous 

 Flora of Japan, still incline to the opinion that the Angiosperms 

 may have sprung from unknown herbaceous plants with a simple 

 floral structure. AVe cannot enter on the discussion here, but 

 the Cycadophyte theory of the origin of Angiosperms is at 

 any rate tenable, and, if contirmed, will afford a strong support to 

 Dr. Gaskell's theory. 



On the whole, though so much is still uncertain, one may safely 

 say that the present tendency of botanical o])inion, determined 

 chiefly by pala;obotanical discovery, is favourable to the belief 

 that new advances in organization start from the highest, or 

 rather from very high, preceding types. Probably the latter, 

 more guarded way of putting the case is the better ; the highest, 

 in the sense of the most differentiated types, may have been 

 usually too far committed to special lines of adaptation to have 

 afforded suitable material for new developments. 



As a type of modern opinion on the evolution of the higher 

 plants, influenced by the conception of the thalloid origin of the 

 Cormophyte, we may suitably take the views of Prof. Lignier. 



