ORGANIZATION OF VOLKMANNIA DAWSONI. 29 



Philosophical Society of Manchester, Third Series, vol. iv. 

 p. 248) ; and I have not the slightest doubt that it repre- 

 sents a true Calamitean fructification. The reasons for 

 this firm conviction are given in the memoir refered to. 



But Mr. Binney also figures a third form (tab. vi. fig. 4), 

 in which the spikes have a much more lax habit. The 

 bracts fringing the bractigerous disk do not embrace the 

 sporangia, but project from beneath them in a rigid manner, 

 leaving the sporangia, loosely located between each verticil- 

 late bractigerous disk, conspicuously exposed to view. 

 The same type of fructification has recently been found in 

 carboniferous shales exposed in a railway- cutting at Huy- 

 ton, near Liverpool, by the Rev. H. Higgins. 



In a second, brief memoir (" On the Organs of Fruc- 

 tification and Foliage of Calamodendron commune (?)," 

 Memoirs of the Literary and Philosophical Society of 

 Manchester, Third Series, vol. iv. p. 218), Mr. Binney 

 has figured a second specimen of what I believe to be the 

 true Calamitean type of fruit. 



Mr. Butterworth placed in my hands some months ago 

 a small strobilus which he had found in the Lower Coal- 

 measures near Oldham ; and on investigating its organiza- 

 tion I soon found that it belonged to the third of the three 

 types to which I have directed attention, viz. that with 

 rigid bracts and exposed sporangia. Its internal structure 

 demonstrates that it is altogether different from either of 

 the other two types referred to, and evidently belongs to a 

 different plant. A fragment of the fruit, which we have 

 retained unsliced, demonstrates its close resemblance to 

 Mr. Binney's tab. vi. fig. 4. 



The spike or strobilus now to be described consists of a 

 central axis, sustaining successive concavo-convex disks, 

 which divide at their peripheral margins into a considerable 

 number of long, stiff, slightly curved bracts. Between 

 each of these bractigerous disks is a single layer of spo- 



