2 Watson, On the Ulodcndroid Scar. 



species which occur in the Ulodendroid condition bear 

 their cones attached to the fine ultimate twigs. 



It seemed to him very unHkely that a Lycopod should 

 bear cones in two distinct ways, so he was forced to 

 discover some other organ to take the place of a cone, 

 and, remembering the bulbils of Lycopodiuvi sclago, 

 applied the idea to Lcpidodendron. 



2. Another idea, due to Carruthers, is that the scars 



represent the bases of roots which arose adventitiously on 



the stems and were attached to the whole area of the scar. 



This view has been combatted by Williamson and 



Kidston. 



The theory that I intend to support in this paper is 

 that the scars are those of branches which were attached 

 to the whole area of the scar. 



In a recent paper (Watson :07) I described the cone of 

 BotJirodcndron iiuindnm Will, and shewed that it did not 

 belong to Ik iiiiuutifoliiiui, Boulay, but probably to B. 

 punctatinn, L. & H. 



This cone is extremely small, less than a centimetre in 

 diameter, and quite short, and it is very difficult to see how 

 it could have produced the enormous Ulodendroid scars 

 which often occur in B. piinctatuiii. If it be suggested 

 that the Ulodendroid scars grew after formation more 

 difficulties are raised, for, whilst it is certain that Lepido- 

 dendroid stems increased in diameter by secondary 

 growth, it is very unlikely that they would elongate verti- 

 cally after becoming sufficiently adult to bear cones. If 

 these scars did grow appreciably I think that the ten- 

 dency of such growth would be to produce scars 

 broader than high, and I think no examples of such scars 

 are known. This fact alone leads one to suppose that the 

 organs producing the scars must have been attached to 

 the stem until the cessation by death or otherwise of 



