K.— BOTANY. 205 
green Alge, a fact more fully recognised on the Continent than here in 
England. In mycology, Marshall Ward, in his investigations on Hemileia 
mycoidea, and on-the digestive action of the hyphe of parasitic fungi laid 
the foundation of the modern British school. Of a later date Blakeslee’s 
discovery of heterothallism was of the greatest importance and led to far- 
reaching results. Passing on to the vascular cryptogams, Bower, after a 
few casts here and there, settled down to the study of development and 
produced a memorable series of memoirs on the spore-producing members, 
and on the phylogeny of the Filicales. Other notable contributors were 
Belajeff, Campbell, Kny, Le Clere du Sablon, Bertrand and Lang. 
A great contribution to our knowledge during this period was given 
by the paleontologists. For some time it has been suspected that certain 
fossil plants were intermediate between the ferns and the gymnosperms. 
Stur and Williamson recognised the occurrence of fern and gymnosperm 
characters in certain fossil plants, and with the increase of evidence a 
separate phylum was recognised and named Cycadofilices by Potonié in 
1899. Later, in 1906, Oliver and Scott made known their observations on 
the seed-like structures attached to the fronds of Lyginodendron. Further 
work revealed that Lagenostoma, Trigonocarpum, Physostoma and other 
fern-like plants were reproduced by seeds of a cycadean type. This 
discovery of the Pteridosperms is the brightest jewel of paleeontological 
study. Passing on to the gymnosperms the work of Strasburger and 
others was continued and many gaps in our knowledge, especially of the 
gametophytes and embryology, were filled; and in this Arnoldi, 
Strasburger, Lawson, Thomson, Coulter, Chamberlain, Coker, Webber, 
and other botanists of the American School took a prominent part. But 
of all these investigations, the most sensational was the discovery in 1896 
of the motile sperms in Ginkgo and Cycas revoluta by Hirasé and Ikeno, 
respectively. Mention also must be made of Wieland’s important work 
on Cycadeoidea and other fossil cycads, the stimulus of which was imme- 
diately felt. 
Like investigations were pursued in the angiosperms, in which many 
of the same botanists were active together with Treub, Guignard, Campbell, 
Duncan Johnson, Benson and others. The discovery of chalazogamy by 
~Treub in 1891, and of double fertilisation in Liliwm and Fritillaria by 
Nawaschin in 1898 provided two thrills. 
Cytology.—This progress was accompanied by that of detailed cytology 
which immediately reacted to the conception of Strasburger and Weismann 
that the nucleus is the bearer of heridital qualities (1884). The reduction 
in the number of chromosomes was discovered in the parasitic worm 
Ascaris by van Beneden in 1883; the next year Strasburger observed it 
in the angiosperms and this was followed by similar observations by 
Overton and by Farmer in other groups. Thus was initiated a period 
of intense cytological study, as the results of which were the revelation 
of the main cytological facts and the nuclear correlations in the sequencies 
of life histories of the main groups of plants and of aberrant species. 
Interest gradually faded, and it was not until after the rediscovery of 
Mendel’s work and the consequent impetus given to plant breeding and 
genetics, that cytology again came to the fore. One further remark has 
to be made: the cytological investigation of malignant growths by 
