18 INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 



DESCRIPTION OF PLATE IV. 



Scini-diagrawinatic transverse sections of steins; size reduced to two-sevenths of given 



magnifications. 



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

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

 stereome ring, ph l ; region of the inner phloem, /V/, ; xylem, xy; cortex, c.i; 

 epidermis, ep. X 44. 

 a. Initial appearance of meristem,//. 



/;. Appearance of supplementary meristems, m^w.,; position of groove, _>y thick- 

 walled parenchyma surrounding meristems,//. 



c. Differentiation of secondary bundles, b\ , $ 2 , b , t , etc.: callus, cl. 



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



and of stereome ring,///.. ; region of inner phloem, ///,. xylem,. iy., /cambium, c 2 . 



e. Union of secondary bundles with primary ring. 



f. Last stage before complete fusion with primary ring. 



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

 tuberance. Lettering as before. X 18. 



a. Initial appearance of meristem, ;//. 



b. Differentiation of secondary bundle-ring, b.,, 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, k. 



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



a. Appearance of a single meristem, in. 



b. Development of supplementary meristems, tti { , ;//., , t/i. A , etc. 



c. Differentiation of meristems into ring of secondary bundle-groups, b\ , />., , f>-,,, etc. 



d. Appearance of lysigenous cavity, ca. 



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



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

 p/i t ; xvlem, xy. 2 ; 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 3. 4a 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. 



