CONIFERALES (PINACEAE) 249 



of an axillary shoot, which stand transversely, and which become 

 coalescent by their adaxial (posterior) edges, the vascular bundles 

 thus necessarily showing inverse orientation. As this normal behav- 

 ior of the leaves of Sciadopitys exactly parallels what was claimed 

 by Braun for the ovuliferous scale, the results of Von Mohl 

 are almost in the nature of a demonstration. 



In 1876 Stenzel described (21) striking abnormalities in cones 

 of Picea excelsa. In one cone leafy axes occurred in the axils of the 

 bracts, the first two leaves resembling ovuliferous scales more than 

 ordinary fohage leaves in texture. In other cones the abnormalities 

 recorded by Dickson (9) were observed. In still other cones he found 

 the two parts of the ovuliferous scale in all stages of coalescence. 

 All of his material confirmed Braun's view that the ovuliferous scale 

 is made up of the first two leaves of an axillary shoot, which stand 

 transversely, and are connate by their adaxial edges. In reviewing 

 Stenzel's paper, Englemann reported (20) similar abnormalities 

 in cones of Picea Englemannii and Tsuga canadensis. 



In 1879 Celakovsky began publishing upon the subject, and 

 has constructed a theory (24, 26, 32, 47) intended to unify the puzzling 

 diversities of structure. He regards the ovuhferous scale as the 

 representative of an axillary shoot, but formed directly rather than as 

 an axis with two distinct lateral leaves, which is a statement of the 

 ontogeny rather than of the phylogeny. In this scale he sees the 

 modified and blended outer integuments of the two ovules. There is, 

 therefore, no true carpel present; it is represented by a single ovule, 

 which is borne by a branch of the second order. In brief, from the 

 standpoint of phylogeny, this is the reduction of a leafy, ovuliferous 

 branch to its ovules. The foliar origin of the outer integument is 

 Ihe thesis of Celakovsky, and this really brings one around again 

 to the foliar nature of the ovuliferous scale and Braun's theory. A 

 related view is that of Kubart (103), who from a study of Juniperus 

 concludes that the ovuliferous scale is an aril. 



In 1892 Bessey pubhshed (67) the view that the staminate and 

 ovulate cones are strictly homologous, and that the ovuliferous scale 

 is a chalazal development of the ovules. "The sporophyll enlarges 

 or remains small just as the chalazal development of the ovule into 

 a scale is more or less pronounced." 



