162 pkooeedinus of the academy of [1894. 



contributions to life histories of plants, no xi. 

 by thomas meehan. 



On the Morphology of Bractless Inflorescence. 



In various papers I have given illustrations to demonstrate that the 

 variety of inflorescence known as extra-axillary results from the 

 sudden arrestatiou of a growing shoot, and the immediate growth of 

 the axillary bud, which pushes aside to a lateral position the former 

 leader and effectually takes its place, only to be itself pushed aside 

 by another developing axillary bud, when the proper time for that 

 development has arrived. 



Although this explanation is fully satisfactory so far as bracteated , 

 inflorescence is concerned, it does not explain the morphology of the 

 naked flowered class, the exact nature of which has never been de- 

 termined, and which, hitherto, I have never been able to understand. 



One has only to read the chapter on "Inflorescence " in "Sach's 

 Text Book " (English edition, p. 519 and following) to learn how con- 

 fused and uuphilosophical are prevailing notions concerning the na- 

 ture of the various forms of inflorescence. That ' ' Boraginacese 

 and Solanacere" present an inflorescence determined by " the re- 

 peated dichotomy of an axillary bud," is better expressed by my 

 proposition that it is determined by " the assumption of leadership by 

 the axillary growth ;" but though it is clear to Sachs that "the 

 ultimate floral axes or pedicels of the flowers " are " not axillary 

 in Aroidete, Crucifene, &c.," he still insists "that every inflor- 

 escence originates from the normal terminal branching of a growing 

 axis." " If bracts are conspicuously developed, the lateral axes 

 arise in their axils ; if they are inconspicuous or abortive, the lateral 

 axes of the inflorescence are not axillary, but their mode of branch- 

 ing and growth remain the same as if the bracts were present." 

 Though long satisfied that this diagnosis of naked inflorescence was 

 wrong, and that there never had been theoretical bracts to abort, I 

 have not, until now, been able to perceive that inflorescence is not all 

 constructed on one plan ; and that naked inflorescence, in particular, 

 does not need the theoretical conception of bracts and axillary buds 

 to account for its character. 



