THE INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 



By Alice Adelaide Knox. 



The definition of fasciation given by the earher writers includes plants 

 with axes which, normally round or polyf^-onal, have become flat, and 

 which, wholly or in part, develop through a linear instead of a cone-shaped 

 growing- region. Such stems are commonl}^ referred to as banded or ribbon- 

 shaped; they produce abnormal numbers of leaves and flowers; they possess 

 an altered phyllotaxy; and they usually show bifurcations, or splitting-s, 

 somewhere throug'h their leng-th. The last tendency is so marked that 

 fasciation may be said to include two tendencies — one toward the enlarg-e- 

 ment and another toward the division of the axes affected. 



Ring-fasciations have circular growing- reg-ions , and the upper part of the 

 stem is shaped like a funnel with a cavity continually wider toward the top. 

 The funnel commonly breaks on the side, and the stem finally becomes 

 flat; for this reason they, too, come under the head of the banded forms. 

 The various torsions of stems of this character described by Godron (4),* 

 Masters (3), and others, seem to be caused by inequalities of growth result- 

 ing- from injuries on the concave side. The fact that the curves may b.e 

 caused by injury is referred to by Nestler (7) for Sambucus nigra and So?i- 

 c/ius palustris, and will not be especially noted in this paper. Plate i, and 

 plate II, figs. 1 and 3, give an adequate idea of the vertical development of 

 fasciated axes . The material for the research presented was gath-ered from 

 the Oenotheras of Dr. D. T. MacDougal's experimental ground at the New 

 York Botanical Garden and from the plants of a waste field of O. bie finis 

 in Bedford Park, New York City. Many years ago Knight, (l) advocated 

 enrichment of the soil for the culture of cockscombs, and de Vries also 

 has repeatedly em])hasized the necessity of plenty of fertilizer. The experi- 

 mental garden provided the requisite conditions, but although fasciations 

 were more abundant in the rich ground their prolific production on plants 

 that grew wild in the sandy waste land illustrated the force of de Vries 's 

 further conclusion (19) that the innate character of the plant is more 

 important than the environmental factors, significant as he deems these 

 to be. 



The life-cycle of biennial primroses divides itself into (a) the rosette stage, 

 and (^)"the adult stage, when the flowering stalks develop and fruit. - The 



*The figures in parenthesis refer to the bibliography, page i8. 



