PROGRESSUS REI BOTANIZE 253 



during the past decade ; Mr. W. Bateson writes in English on the 

 progress of genetics since the rediscovery of Mendel's papers; and 

 Dr. Friedrich Czapek describes in German the progress of the 

 physiology of plant-nutrition since 1896. 



Dr. Laurent divides his subject-matter into four sections, under 

 the titles — Investigations, Methods, Facts, Results, The regions 

 investigated include in the southern hemisphere the extreme south 

 of South America, where Mr. Dusen has studied plant-beds of 

 presumed oligocene age, and Australia, where Mr. Deane finds 

 reason to modify considerably the conclusions previously formed by 

 Ettingshausen. M. Fliche has studied the cretaceous beds of 

 Madagascar, and M. Zeiller the region of Lake Tchad in Central 

 Africa; in tropical South America work has been done in Bolivia, 

 Brazil, and Colombia, chiefly by Mr. Engelhardt, and the results 

 indicate a great homogeneity in the flora, which resembles that of 

 the present day. In Japan, Mr. Yokoyama has found in beds of 

 neocomianage plants which are a continuation of the upper Jurassic 

 types and analogous to those found in Europe. 



In discussing methods, Dr. Laurent adversely criticizes the 

 method of the older palseobotanists in matching imprints of fossil 

 leaves, often fragmentary or badly preserved, with those of recent 

 plants, a practice which led to the description of numerous species 

 of little or no value, and to general conclusions which a more care- 

 ful study does not uphold. The character of the venation of the 

 leaf remains the most important character for the worker in this 

 field, as flowers are very rarely preserved, and fruits when found 

 are not associated with the foliage, and the author lays stress on 

 the importance of a careful comparative study of the venation of 

 the various members of the same flora, and of these with known 



types in other floras. 



As regards facts, one of the most important has been the gradual 

 driving back of the origin of angiosperms right to the beginning of 

 the cretaceous age. But up to the present there is no trustworthy 

 information as to the relative antiquity of the two great divisions, 

 Monocotyledons and Dicotyledons. The presumed ancient Mono- 

 cotyledons have been based on incomplete material and yield to 

 further study, while the P rotor hi pis, the presumed primitive Dicoty- 

 ledons originating in the Lias, are now regarded as ferns of the 



PlatyceriiiM type. The question as to the former presence of 

 Proteacea in Europe remains still unsettled. Dr. Laurent draws 

 attention to a remarkable point in this connection ; while on the 

 one hand a large number of leaves have been referred to this family, 

 there is an almost total absence of fruits and seeds, though these 

 structures in the Protectees are well adapted for preservation as 



fossils. 



In discussing results, reference is made to the first appearance 



of Gamopetala. Facts observed prove their great antiquity, as Serium 



and Viburnum are recorded from cretaceous beds; but the great 



majority of their representatives are unknown to us, while, on the 



other hand, apetalous orders are well represented in these early 



floras. Dr. Laurent points out that this contrast may be due to 



