58 



PRINCIPLES OF PLANT-TERATOLOGY. 



3. DISRUPTION. 



The structure of the normal maize-cob is the result 

 of a phenomenon which would seem to be unique in 

 the vegetable kingdom.* It consists of the fusion of 

 numerous spikes with flattened rachis, each bearing 

 two rows of female spikelets, to form the thick female 

 inflorescence usually termed the " cob." This cob is 

 often spoken of as a " fasciation," but inasmuch as it 

 is obviously not, as all fasciations are, a single 

 branching structure, but a compound one, due to the 

 congenital union of a number of branches of the same 

 inflorescence, the abnormality about to be described 

 must be placed under a distinct heading which may 

 be termed " disruption." This consists in the appear- 

 ance of the "cob " as a copiously-branched paniculate 

 inflorescence, closely resembling, in its extreme form, 

 the male inflorescence ; and is due to the dissolution 

 of the compound organ into its original separate parts. 

 Blaringhem, by artificial torsion of the stem, induced 

 the same phenomenon, which must certainly be re- 

 garded as a reversion to an ancestral condition in 

 which the inflorescences of both sexes resembled each 

 other, or in which both sexes were intermingled in 

 one and the same paniculate inflorescence. Blaringhem 

 regards it as a reversion to the type of inflorescence 

 at present exhibited by the grass Euchlasna mexicana 

 (Reana) which he considers to be in all likelihood the 

 primitive wild ancestor of Zea Mais (PI. XXXIX, figs. 

 13 and 14). 



BIBLIOGRAPHY. 



Ascherson. — " Bemei-kungen iiber aestige Maiskolben." Sitz- 

 ber. hot. Ver. Prov. Brandenb., Jahrg. xxi (1879), 

 pp. 133-138. 



Blaringhem. — Mutations et Traumatismes. Paris, 1908. 



* It is unique only as regards the fusion together of axes ; the type of 

 foliage obtaining in the Cupressineae is due to the congenital fusion with 

 the axis of the leaves which, in the juvenile or " Retinospora " condition, are 

 quite free. 



