May 1900.] BOTANICAL SOCIETY OF EDINBUKGH 293 



biliferous axis bears a long-stalked lateral cone of small 

 size. The upper half of this cone is sterilised, its 

 sporophylls resembling ordinary leaves ; of the basal 

 half, the sporophylls on the adaxial side are fertile, 

 those on the abaxial side sterile. In consequence of 

 the greater growth on the adaxial side, due to tlie 

 developing sporangia, the cone has been curved over 

 towards its abaxial sterile side. 



Higher up on the opposite side a second lateral cone, 

 almost sessile, arises very close to the base of the terminal, 

 which gives off a lateral branch cone on the right near its 

 base. . 



Fig. 1 shows a further stage in the process of steril- 

 isation. The lower lateral cone, again long-stalked and 

 arising about half-way up the axis, is completely sterilised, 

 with the exception of some half-dozen sporophylls on the 

 adaxial side. These fertile sporophylls, however, like the 

 sterile ones, have all the characters of ordinary foliage 

 leaves, so that the process of metamorphosis of sporophylls 

 into foliage leaves in this case w^ould appear to have 

 outstripped the abortion of the sporangia. The other 

 structures on the axis are similar to these on Fig. 9, 

 save that the fertile spikes are better developed, and the 

 left lateral cone originates farther down the axis, and is 

 stalked. 



Figs. 11 and 12, like 7 (Plate I.), show the extreme 

 case where the lower lateral cone is completely sterilised 

 and purely vegetative. The sporangia have aborted, and 

 the cones have the appearance of small lateral foliage 

 shoots on short stalks. 



In Fig. 1 1 another noteworthy feature can be observed : 

 the part of the axis below the insertion of the sterile 

 cone shows a gradual passage by increase in size from 

 the characteristic appressed scales of the normal strobili- 

 ferous axis into foliage leaves. The terminal cone bears 

 a lateral branch cone on the left, a quarter of an inch 

 above its base ; while a second lateral cone of small size 

 arises directly from the axis on the right, just at the base 

 of the apical. 



A curious trident appearance is produced in Fig. 12 

 by the branching of the terminal cone. It gives off a 



