322 LYCOPODIALES 
is doubtful what is the evolutionary relation between the distal and the 
basal insertion of the sporangium upon the sporophyll ; whether the one 
or the other is the more primitive in the Lycofodiales must be left for the 
present open, but it is evident that such differences as these are of degree 
only, in a type which is constant as regards the numerical relation of the 
sporangia to the sporophylls, and in the coincidence of the median planes 
of both of those parts. There seems little reason to hold that these 
peculiarities of Spencer7tes are archaic relatively to those of the ordinary 
Lycopodinous type. Comparison does not make it necessary, nor even 
probable, while stratigraphically the ordinary Lycopod type is quite as 
early as Sfencerites. 
The same relation of sporangium to sporophyll as is seen in the 
living Lycopods is maintained in the Lepidodendroid cones, which are 
Fic. 168. 
Lepidostrobus Brownit. A radial section traversing the axis, a sporophyll, and a 
sporangium. In the latter numerous spores are seen partially filling it, while sterile 
processes project upwards into the cavity. (From Sowerby’s drawing.) 
known in many cases to bear ligules, and to be heterosporous, thus 
corresponding more especially to the ligulate series of the Lycopodiales ; 
but this may possibly not be the case for all of them. An examination 
of the details of the sporangium will naturally be best carried out in the 
best preserved specimens, though these may not be generally typical of 
all others. Lepidostrobus Brownit, Schpr., is probably the best preserved 
of Lepidodendroid cones, and it will therefore be taken first. The large 
silicified specimen in the British Museum was first described by Robert 
Brown, with drawings by Sowerby.!. The original specimen was about two 
inches in length, and of about the same diameter: it was evidently only 
the upper half of a strobilus, as the internal structure, which is preserved 
with singularly little distortion, shows to be the case. It has been cut 
into transverse, radial and tangential sections, and consequently a very 
adequate knowledge of the details can be obtained. The central axis 
Zinn. Trans., vol. xx. See also Aftsc. Bot. Works of Robert Brown, vol. i., p. 583+ 
