20 INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 



DESCRIPTION OF PLATE V. 



[Prawn with an Abbf> camera lucida and reduced to one-third of given magnincatious.1 



FIGS i, 2, 3. Transverse sections of stems of O. biennis. Successive stages in the early 

 development of a groove-fasciation. Aleristem, //// thick-walled parenchyma, 

 pp; medullary parenchyma, ////>, cambium, c; outer phloem of primary bundle 

 ring,///) ; inner phloem of same ring, ph.,. Fig. i shows the lowest section of 

 the meristem (plate iv, fig. ia). The dark shading in the meristem indicates 

 intercellular secretions. At x the cambium has been destroyed. X 430. 



FIG. 2. Drawing of meristems in plate iv, fig. \b. Two meristems (///, , /;/,) appear in the 

 break in the ring. < 430. 



FIG. 3. Drawing of two groups of secondary bundles, showing first differentiation of 

 vessels. Secondary bundle-groups, l> l , b. L . X 560. 



FIG. 4. O. cruciata. Diagram of longitudinal section of a cylindrical protuberance. 

 Bundle-ring, b; callus, cl; cortex, c.v. X 25. 



FIG. 5. O. cruciata The same as fig. 4. Group of callus cells from the apex. X 360. 



FIG. 6. O. cruciata. The same as figs. 4 and 5. Drawing of portion of apex of bundle- 

 ring opposite point marked z in fig. 4. Spiral ducts run transversely across 

 the tip. 



FIG. 7. O. cruciata. Diagram of longitudinal section of apex of plant shown in fig. 8. 

 Sections of vegetative circle, vc; callus, cl; primary bundle ring, b. X iS^/. 



FIG. 8. O. cruciata. Longitudinal section of apex of fig. 7 at cl. Callus, cl; proto- 

 phloem, pJi^, ph.,; proto-xylem showing spiral ducts, xy . This is an early 

 stage in the formation of a protuberance. 360. 



FIG. 9. O. cruciata. Diagram of cross-section of base of fasciated rosette which shows 

 traces of injury. The oval shape of the pith shows the beginning of the 

 flattening. Phellogen, pg; bark, bk; meristems in pith, ////;/, callus at point of 

 inhibition of growth, cl. X 8. 



FIG. 10. O. cruciata. Diagram of longitudinal section of bifurcated tip, showing posi- 

 tion of callus, cl. At q the bundle-elements run irregularly in a confused 

 tangle. K is a small protuberance. X 52. 



FIG. ii. O. cruciata. Drawing of longitudinal section of apex similar to fig. 13. An 

 incision surrounded by hypertrophy and meristematic divisions. The con- 

 tents of the cavity are stained reddish purple. C 560. 



FIG. 12. O. cruciata. The same as fig. u. Cells in pith surrounding the lower end of 

 incision. The blackened edges indicate purplish discoloration between the 

 cells. The cells hypertrophy and close in around the incision without dividing. 

 X 480. 



FIG. 13. O. cruciata. Diagrammatic longitudinal section of an injured tip similar to the 

 one pictured in figs. 11 and 12. The apex seems to be slightly fasciated, and 

 the stem is bifurcated. /, injury. X 25. 



FIG. 14. O. cruciata. Transverse section of early stage of ring-fasciation. The inter- 

 cellular conditions indicate that it has been injured. Cf. fig. 12. m, two cells 

 of the meristem. X 560. 



FIG. 15. O. cruciata. Transverse sections of ring-fasciation in fig. 14 at a more advanced 

 stage. Secondary bundle-ring, b.,,. In the center of the pith is a cavity sur- 

 rounded by hypertrophied cells and meristematic divisions. This is not the 

 beginning of the lysigenous cavity of the ring, which occurs some sections 

 above. X 430. 



FIG. 1 6. Transverse section of flowering stem just below the point of fasciation, showing 

 inhibition in the formation of wood at xx. X 25. 



FIG. 17. Raiuiannia odorata. Cross section of young bifuricated rosette, showing injury 

 to cortex and inhibition in the development of the bundle-ring at .r.r. < 92. 



