VOLUME XLVIl 



NL'MKKR 5 



Botanical Gazette 



MAY igog 



_ 



MEG 



MICROCACHRYS 



Robert Boyd Thomson 



(with plates xxii-xxv) 



In the Coniferae great importance attaches to " inverse orientation" 

 as a criterion for determining the character of the fertile scale in the 

 megasporangiate cone. The followers of Braun see in the inversion 

 of the ovulif erous scale bundles an indication of the " brachyblast 

 character of this structure. Sachs and Eichler, the exponents ot 

 ^e "ligular" theory, look upon the inversion as a feature wuci 

 characterizes the vascularization of a ligule or of an appendage or the 

 simple sporophyll. Celakovsky partly combines the two views 

 and seems to homologize many of the diversified megasporang.ate 

 features of the gvmnosperms. In the present study some neglec tea 

 Phases of the inversion of the sporangial supply bundles of both the 



aminate and ovulate cones are given prominence, and data are 

 advanced to show the homology of the micro- and megasporopnyll in 



^axegothaea and Microcachrys. . ,. 



The gross features of a fruiting branch of Saxegothaea are indi- 

 cated in^g. 7 . The megasporangiate cones are borne terminally o 



I, 2), the microsporangiate ordinarily in the axils 



,.<. -: n„ :„ » terminal position (fig. 3)- inc 



(figs 



-o^ H u, {U ig iaie C one, at tne siage muiwiw »*j- - edicel 



^ beset with the bracts which earlier inclosed it. Later the p 

 Agates and a lax arrangement of the bracts is evident {Hg. 4- 

 Sti " later the pedicel becomes much more elongated and relatively 

 *? slender. The bracts, sporophylls, and foliage leaves are sp.ra y 

 arra nged, and gradations in form are evident, the bracts gradating 



345 



