194 ARTHUR HENFREY 



the subject. This Golden Age was contemporaneous with, and 

 immediately dependent on, the rise of a group of young botanists 

 in the Fatherland, a group which included von Mohl, Schleiden, 

 Hofmeister, Nageli, Cohn and De Bary. Later it was reinforced 

 by Sachs, who in addition to being a brilliant physiologist was a 

 gifted writer who did much to establish scientific botany on a 

 sound footing. It is impossible to overestimate the debt due to 

 Sachs, particularly for his great Textbook of Botany, which at the 

 right psychological moment brought the whole of the modern 

 work between the covers of a single volume. 



It was with the dawn of this period that Henfrey identified 

 himself. In the 15 years of his active career (1844 1859) he 

 devoted himself very largely to making his fellow-countrymen 

 acquainted with the newer aspects of botany. More particularly 

 it was the recent discoveries as to the reproduction and life history 

 of the Vascular Cryptogams that specially engaged his interest 

 the researches which broadly speaking we associate with Hof- 

 meister to-day. 



Before we go on to speak of the sexuality of the Cryptogams 

 however, a few words may be devoted to that of the flowering 

 plants. 



Sexuality of Flowering Plants. At the period when Henfrey 

 entered on his career as a botanist no reasonable doubt remained 

 as to the existence of sexes among the flowering plants. The 

 theory of the sexual significance of the organs of the flower, 

 brilliantly founded by Koelreuter in the previous century, had 

 been perfected with a great volume of experimental proof by 

 K. F. Gaertner the son of Joseph Gaertner of Carpologia fame. 



By 1830 the mechanism of fertilisation came to light in 

 Amici's discovery of the pollen tube which he traced from the 

 stigma to the micropyle. The microscopic aspect of the problem 

 was taken up with great energy by Schleiden and brought to 

 the forefront as the burning question of the early forties. The 

 theory of Schleiden, which applied in particular to the flowering 

 plants, made its influence felt to such an extent in the search 

 for evidence of sexuality among the Cryptogams, that we may 

 conveniently state in a few words in what it consisted. 



Schleiden traced the pollen tube into the micropyle, and 



