444 Scientific Proceedings, Royal Dublin Society. 



PLATE XXXI. 



1. P. zonale. Isolated occurrence of vessels on sylem-free side of central bundle. 



x45. 



2. P. zonale. Splitting ot central bundle, x 45. 



3. P. zonale. First a^opearance of cambium on normally xylem-free side of 



phloem of central bundle, x 45. 



4. P. zonale, B, 1375, 24/4-2/7. x 200. Proliferation of this cambium. Note 



this is a leaf grafted on a stem. 



PLATE XXXII. 



1. P. zonale, B, 1375, 24/4-2/7. x 45. Shows secondary increase in central 



bundle. Note length of time grafted — about ten weeks. 



2. P. zonale. Secondary increase and fusion of upper bundles of normal petiole. 



This was grafted on 21/4/13, and cut down 2/6/14 — just six weeks. 



3. P. zonale. Interfascicular cambium development in already differentiated 



cortical cells preparatory to giving stage shown in last fig. x 200. 



4. Solanum Balbesii. T. S. normal petiole, x 25. 



PLATE XXXIII. 



1. S. Balbesii. Secondary wood developed in grafted petiole, x 25. 



2. S. Bichardi. T. S. normal petiole, x 25. 



3. S. Bichardi. T. S. petiole of leaf grafted on Tomato 10/4/13, removed 29/7/14. 



x25. 



4. P. zonale. Leaf-cutting, x 20. Shows starch and abnormal periderm. 



PLATE XXXIV. 



1. P. zonale. Leaf-cutting. Shows periderm, x 45. 



2. P. zonale. Leaf-cutting. Shows activity (tuberous ?) of medullary cells, x 45. 



