SECTIONAL TRANSACTIONS.—K. 357 
genera Lophosoria and Metaxya lead on unmistakably to the Cyatheacew, which are 
also superficial. Between these two main lines may be placed Plagiogyria, which 
appears as a separate, relatively primitive stock, and finds a natural relation down- 
wards with the Osmundace, and especially with Todea. 
The main mass of the Leptosporangiate ferns appear related to these three inter- 
mediate lines in the following way. They constitute six main sequences, which may 
be designated after the leading genus of each, viz., the Davallioidee and Pteroidee, 
which may be linked with the marginal Dicksoniacez; the Gymnogrammoides 
linked naturally through Llavea and Cryptogramme with Plagiogyria ; the Blechnoidez 
and Dryopteroidez linked with the superficial Cyatheacez; and lastly, the Dipteroidee, 
which may be regarded as derivative from some stock of Dipteroid-Matonioid nature. 
3. Mr. J. Watton.—Features of Biological Interest in the Foliage of 
some Paleozoic Plants. 
A critical examination of fossil Equisetalean foliage of the incrustation-type and 
a comparison with that of Hquisetum reveals some interesting similarities and differ- 
ences. The presence of hydathodes in Annularia sphenophylloides, the xeromorphic 
structure of A. radiata, and the melasmatic (?) tissue in the lamina of A. dubia are 
some of the features of interest in the group. The peculiarities of some Pterido- 
sperm foliage are also worthy of attention from the point of view of the information 
they may give as to environmental conditions. 
4, Prof. J. Prinsttry.—Light and Growth. 
An attempt is made to bring to one common focus the phenomena of etiolation, 
including the remarkable morphological and structural changes induced by very 
brief exposures of etiolated plants to light, and the facts of phototropism, as exhibited 
both in the higher plants and in fungus hyphae. 
An attempt is made to interpret the phenomena -of phototropism without the 
employment of the terms ‘ stimulus’ and ‘ response.’ 
AFTERNOON. 
Excursion to Eling and Hythe. 
. Friday, August 28. 
Mornine. 
5. Joint Discussion with Section E on The Evolution and Colonisation 
of Tidal Lands. 
(a) Prof. F. W. Ottver, F.R.S. 
Their great extent; difficulty of definition. The tidal zone a thing apart, having 
its own physical characteristics, usages, traditions, mentality of inhabitants, &c. 
The usual plant coverings of accreting and decreting shore lines. Richness of 
flora in relation to type of shore line. 
Vegetation, essentially sedentary, here as elsewhere, gives cohesion to and 
stabilises migrating soils. Its efficiency illustrated by examples of its operations : 
depots of shingle ; sand dunes; salt marshes and mangrove swamps. Resistance to 
erosion. Pioneer plants and the successions. Natural and artificial reclamations— 
Holland and elsewhere. Relation to navigation. Possibilities and limitations in 
coastal control. 
(b) Prof. J. W. Gregory, F.R.S. 
The tidal lands, rendered serviceable and stable by a carpet of vegetation, are due 
partly to the cutting back of the land by the sea, but mainly to the deposition of 
sediment in sheltered positions. The main processes are threefold; the formation 
of a bar which may arise as a deltaic shoal or as a bay-head beach ; the formation of 
a spit by longshore drift, and sedimentation in the quiet water behind the bar or spit 
producing estuarian plains with, for a brim, their residual lakes or broads. These 
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