66 ON THE FOSSIL FLORA OF THE COAL DEPOSITS OF AUSTRALIA, 



similar in plan to that of the living Equisetum arvense, L., but 

 there are two elaters instead of four, and the peltate scales are 

 protected by paleaceous glumes. 



The genus Equisetum is thus denned by Linnseus*. 



Equisetum (No. 1284). 



Fructification es in spicam ovato-oblongam digestce. Singula 

 orbiculata basi deliiscens pluribus valvulis, apice piano peltato 

 connexis. 



This, it will be perceived, makes no reference to the form of the 

 plant, but only to the spike and the sporangia. It was included 

 amongst the Filices. 



The definition of Schimper f remedies this. It is " Fructus 

 spicceformis cylindraceus, oblongus, seu ovatus, sporangiorum recep- 

 taculis peltoidis. Folia in vaginam connata. 



There are nearly twenty species of this genus described from 

 Mesozoic strata, besides some of modern age. The Mesozoic 

 forms are from the Trias, Lias and Oolite, the latter principally. 



Equisetum rotiferum, n.s., pi. vi., fig. 5, 6. Stem cylindrical, 

 closely and faintly grooved, joints approximate below, distant 

 above. Leaves carinate, connate into a sheath, the teeth of which are 

 short, flat, rounded, of equal width throughout, adpressed to the 

 stem. The diaphragmata of the joints and leaf scars of the branches 

 are very distinct, round, with radiate lacunae, varying from 18 to 

 30, and a central orifice. Fructification unknown. 



Very abundant in the grey fire clays above the first seam at the 

 Walloon mine near Ipswich, Queensland % The casts of the 

 diaphragmata are especially numerous, and have a singularly 



* Genera Plantarum, p. 554. Edit. cur. Reichard, Frankfort on the 

 Maine, 1778. 



T Paleontologie vegetale, Vol. I., p. 259. 



X The Walloon mine is about 10 miles west of Ipswich and rather more 

 than that distance from the Bundamba and other seams, which are the 

 oldest Ipswich coal mines, and the seams from which most of the fossils pre- 

 viously described have been taken. The relations between the two beds 

 have not been ascertained, but I have no doubt that they all belong to one 

 carbonaceous deposit, and there seems to be no break. 



