TRANSACTIONS OF SECTION D. 685 



in the Japanese flora. Seven species, while found with the others, enter also into 

 the Mediterranean flora, extending to North Africa: these are Thalictrum minus, 

 L., TJialictrum flavuni, L., Ranunculus rejiens, L., SteUaria aquatica, Scop., Corylus 

 Avellana, L., Zcmnichellia palustris, L., and Cladium Mariscus, Br. With a similar 

 distribution in the Old World, eight species {Bidens tripartita, L., Myosotis 

 caspitosa, Schultz, Suceda maritima, Dum., Ceratophyllum demersum, L., Spar- 

 ganium ramosum, Huds., Potamogeton pectinatus, L., Carex paludosa, Good., and 

 Osmunda regalis, L.) are found also in North America. Of the remainder, ten 

 species {Nuphar luteutn, Sm., Memjanthes trifoliata, L., Stachys palustris, L., 

 Rumex maritimus, L., Rumex Acetosella, L., Betula alba, L., Scirpus paudflonis, 

 Lightf., Taxus baccata, L., and Isoetes lacustris, L.) extend round the north 

 temperate zone, while three {Lynopus europceus, L., Alisma Plantago, L., and 

 Phragmites communis, Trin.), having the same distribution in the north, are found 

 also in Austraha, and one {Hippuris vulgaris, L.) in the south of South America. 

 The list is completed by Ranunculus aquatilis, L., distributed over all the 

 temperate regions of the globe, and Scirpus lacustris, L., which is found in many 

 tropical regions as well. 



The various physical conditions which necessarily affected these species in their 

 difiiision over such large areas of the earth's surface in the course of, say, 250,000 

 years, should have led to the production of many varieties, but the uniform 

 testimony of the remains of this considerable pre-glacial flora, as far aa the 

 materials admit of a comparison, is that no appreciable change has taken place. 



I am unable to carry the history of any existing species of plant beyond the 

 Cromer deposits. Some of the plant-remains from Tertiary strata have been referred 

 to still living species, but the examination of the materials, as far as they have 

 come before me, convince me that this has been done without suflicient evidence. 

 The physical conditions existing during even the colder of the Tertiary periods were 

 not suitable to a flora fitted to persist in these lands in our day, even if the period 

 of great cold had not intervened to destroy them. And in no warmer region of the 

 earth dp these Tertiary species now exist, though floras of the same facies occur, 

 containing closely allied species. The sedimentary beds at the base of the Glacial 

 Epoch contain, as far as we at present know, the earliest remains of any existing 

 species of plant. 



It is not my purpose to point out the bearing of these facts on any theoretical 

 views entertained at the present day : I wish merely to place them before the 

 members of this Section as data which must be taken into account in constructing 

 such theories, and as confirming the long-established axiom that by us, at least^ 

 as workers, species must be dealt with as fixed quantities. 



The following Reports and Papers were read : — 



1. Report of the Committee for arroMging for the Occupation of a Table at 

 the Zoological Station at Naples. — See Reports, p. 254. 



2. 



Report of the Committee for continuing the Researches on Food-Fishes 

 and Invertebrates at the St. Andrews Marine Laboratory. — See Reports, 

 p. 268. 



3. On the Value of the ' Type System ' in the Teaching of Botany. 

 By Professor Batlet Balfour, F.R.S. 



4. 



Remarks on Physiological Selection, an Additional Suggestion on the Origin- 

 of Species, by 0. J. Romanes, F.R.S. By Henkt Seebohm, F.L.S. 



