18 INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 



DESCRIPTION OF PLATE IV. 



Semi-diagrammatic trans-verse sections of stems; size reduced to two-sevenths of given 



magnifications. 



SERIES i. O. biennis. Successive stages in the development of a groove-fasciation 

 Medullary parenchyma, nip; region of cambium, c; region of outer phloem and 

 stereome ring,///,/ region of the inner phloem, pli,; xylem, xy; cortex, ; 

 epidermis, ep. X 44. 



a. Initial appearance of meristem,//. 



/;. Appearance of supplementary meristems, /n\,i.,; position of groove, ,- thick- 

 walled parenchyma surrounding meristems, pp. 



c. Differentiation of secondary bundles, 6, , (>.,, b.., etc.; callus, cl. 



d. Gradual enlargement and increase of secondary bundles; region of outer phloem 



and of stereome ring,///., .- region of innerphloem, ///,.- xylem, xy., ; cambium, <,. 



e. Union of secondary bundles with primary ring. 



f. Last stage before complete fusion with primary ring. 



SERIES 2. O. cruciata. Development of a fasciation associated with a cylindrical pro- 

 tuberance. Lettering as before. X 18. 



a. Initial appearance of meristem, in. 



b. Differentiation of secondary bundle-ring, />.,, in the pith. 



c. Connection of secondary bundle-ring with the primary ring. 



d. Fusion of the same. 



e. Beginning of formation of protuberance at k. 



f. Protuberance cut off, /'. 



SERIES 3. O. biennis. Development of ring-fasciation. X 25. 



a. Appearance of a single meristem, m. 



b. Development of supplementary meristems, /, , m., , m.. , etc. 



c. Differentiation of meristems into ring of secondary bundle-groups, b l , b., , A, , etc. 



d. Appearance of lysigenous cavity, ca. 



c. Gradual fusion of secondary bundle-groups. Inner epidermis, ep,; inner cortex, 

 ex.,; outer phloem of secondary ring, ph< ; inner phloem of secondary ring, 

 pit,; xvlem, xy, ; pith,//. 



f. Break in side of ring, making a flat fasciation. 



SERIES 4. O. biennis. Four stages of the development of a specimen intermediate 

 between Series i and i 4<z corresponds with y. The secondary bundle-ring 

 arises in the middle and passes to the side, where it fuses with the primary 

 ring. X 20. 



