Veronica Chamaedrys caused by Sorosphaera Veronicae. 43 
and the tumours are derived from the repeated division of one or more 
infected cells. 
4. The primary infection takes place in the vicinity of the growing 
point of the stem. 
5. The parasite is closely allied to Plasmodiophora Brassicae , the 
nuclear division taking place in a similar manner. The wedge-shaped spores 
of the former are, however, to be found in spheres enclosed in a common 
membrane, in contrast to those of the latter, which are free. 
Postscript .—Since the above communication was sent to the Editors of 
the Annals of Botany, a paper by Maire and Tison has appeared in the 
‘ Annales Mycologici ’, vol. vii, No. 3, 1909, on the same subject. It is satis¬ 
factory to find that their figures and interpretations are in the main in 
agreement with ours. The point of entry of the parasite is not noted 
by these observers, nor the observation of Nawaschin as to the method of 
formation of infected areas. 
EXPLANATION OF PLATE V. 
Illustrating the paper by Dr. Blomfield and Mr. Schwartz on Tumours of 
Veronica Chamaedrys. 
Figs. 2, 3, and 4 were drawn with a Leitz No. 6 objective and No. 3 ocular. 
The figures 6 to 21 were drawn with 1-40 homog. oil immersion (Zeiss), 6 to 17 with 
compensating ocular 18, and 18 to 21 with compensating ocular 12. 
Fig. 1. Portion of diseased plant showing tumour natural size. 
Fig. 2. Section of early or young tumour. 
Fig. 3. Section of middle tumour. 
Fig. 4. Section of mature tumour showing sorospheres and amoebulae. 
Fig. 5 a-m. Various stages of nuclear division taking place during the vegetative period of the 
parasite. For description see text. 
Figs. 6-17. Sequence of changes undergone by the organism in the formation of the sorosphere. 
Figs. 6 and 6 a show the chromatin moving to the periphery. Fig. 7 shows the complete dis¬ 
appearance of the nuclei and the formation of the vacuoles. Figs. 8, 9, and 10 illustrate the 
formation of fresh nuclei; Fig. n the first nuclear mitotic division, which is completed in 12; 
Fig. 13 the second nuclear division ; Figs. 14, 15, and 16 the three last stages in the formation of the 
sorosphere. Fig. 17, portion of a sorosphere in surface view. 
Fig. 18. Hypertrophied plant-cell with four nuclei in process of division. 
Fig. 19. The same, showing two nuclei in the spindle stage. 
Figs. 20 and 21. Enlarged plant nuclei. 
