130 LYCOPODIALES [CH. 



in offering suggestions as to the meaning of these large cup- 

 like depressions, and there is still difference of opinion as to 

 their significance. Lindley and Hutton^ described them as the 

 scars of branches or masses of inflorescence. Sir Joseph 

 Hooker 2 speaks of a specimen of Ulodendron, shown to him by 

 Mr Dawes, on which a large organ, supposed to be a cone, was 

 inserted in one of the depressions, but he was unable to arrive 

 at any conclusion as to the real nature of the fossil. While 

 most authors have seen in the scars pressure-areas formed by the 

 pressure of sessile cones against the surface of a growing branch, 

 others, as for example Geinitz^, have described the depressions 

 as branch-scars. Carruthers^ regarded the scars as those of 

 adventitious roots and Williamson referred to them as the 

 scars of reproductive shoots. The depressions vary considerably 

 in size. The Belgian example shown in fig. 211 possesses scars 

 9 cm. in diameter. A specimen of Bothrodendron in the Man- 

 chester Museum from the Lancashire Coal-Measures, to which 

 Williamson^ has referred, bears two rows of scars 11 — 12 cm. 

 in diameter on a stem 112 cm. in girth and 233 cm. long. The 

 scars occur in two alternate series, on opposite faces of the 

 axis, the distance between the successive scars in the same row 

 being 29 cm. The surface-features of this large stem are not 

 preserved. 



Before considering the nature and origin of the scars it is 

 important to remember the considerable size to which they 

 may attain; other points of importance are the occurrence, 

 either in the centre of each depression or in an excentric 

 position, of an umbilicus or slightly projecting boss, in the 

 centre of which is a pit formed by the decay of an outgoing 

 vascular strand. The sloping sides of the scars sometimes 

 bear elevations resembling leaf-cushions like those on the rest 

 of the stem surface. In the specimen shown in fig. 157 the 

 lower margin of each cup shows indistinctly the outlines of what 

 appear to be leaf-cushions, while the rest of the sloping face is 

 characterised by radial ridges, which may be due to bracts or 

 leaves. 



1 Lindley and Button (31) A. '^ Hooker (48), p. 427. " Geinitz (55) A. 

 4 Carruthers (70). s Williamson (72). 



