352 SPHENOPHYLLEAE. 



branchlets undoubtedly belonging to Sphenophyllum, as for instance near 

 Wettin in tolerable abundance. Figures of such objects are to be found in 

 Germar 1 , Geinitz 2 , Schenk 3 , and Schimper 4 , and diagrammatic representa- 

 tions in Grand' Eury 6 . Geinitz and Schimper agree in their accounts of 

 the structure of these spikes, and a careful examination by Schenk 6 yields 

 the same results. Not having devoted any study to them myself, I will 

 adopt Schenk's description of them in the following remarks. He says that 

 the fructification is composed of moderately crowded uniform sporangiferous 

 whorls. The leaves of the whorls are hollowed out at the base, in some 

 cases forming a spur-like pocket, and then ascend so that their apices 

 reach to the whorl next above, or are imbricated upon it. They resemble 

 the foliage-leaves of the vegetative branches in having the anterior margin 

 divided into several teeth. These fertile leaves are exactly superposed in 

 the consecutive whorls in all Germar's figures. If this is strictly correct, it 

 would agree well with the inner organisation of the plant as described to us. 

 On the other hand it would be hard to reconcile or be even irreconcileable 

 with that organisation, if it is really the case, as Schenk thinks, that four 

 leaves were usually united in one whorl. Renault 7 too protests against this. 

 Schenk states that the specimens hitherto examined were not adapted to 

 settle this point. It may therefore be supposed that with better material 

 the number six characteristic of the group will be found also in the fructi- 

 fications. The sporangia stand singly in the hollow of the base of the leaf, 

 which in Sphenophyllum angustifolium is almost spurred : they are lenticular 

 in shape and sessile, and vary in diameter from one to two and a half 

 millimetres. 



Diminutive spikes have been found by Witkowitz with Sphenophyllum 

 tenerrimum in the beds at Ostrau, and as their leaves agree with the leaves 

 of that species in shape and in their dichotomous branching, they may belong 

 to it. They have been figured and described by Stur 8 . The sporangia lie 

 closely crowded together between the leaf-whorls, filling the space between 

 every two leaves ; their insertion has not been exactly ascertained, though 

 Stur inclines to think that they were attached to the axis and not to the 

 base of the leaf. 



Hitherto unfortunately no unquestionable inflorescence of Spheno- 

 phyllum has been found as a petrifaction. Renault 9 met with one frag- 

 ment in the pebbles of Grand' Croix which may possibly belong to the 

 group, but it is involved in too many doubts to be really taken into con- 

 sideration. The bit of spike, which is only four millimetres in length, shows 

 superposed uniform leaf-whorls and a thin rudimentary central xylem- 



1 Germar (1), tt. 6, 7. a Geinitz (5), t. 20. 3 Schenk (2),t. 38, ff. i, 2. 4 Schimper (1), 

 t. 25. Grand' Eury (1), t. 6, ff. 9, n. Schenk (10). 7 Renault (20), p. 283. 



8 Stur (5), p. 222 ; t. 7, f. 14. 9 Renault (20\ p. 303 ; t. 9, ff. 9-11. 



