120 TRANSACTIONS, NATURAL HISTORY SOCIETY OP GLASGOW. 



a few feet. The stems are generally of small diameter, and seem to 

 have been incapable of supporting themselves in an upright position 

 without some external aid. This they possibly obtained by scram- 

 bling amongst other vegetation, and a,s,SpheiiophyUum is unprovided 

 with any means of clasping or twining round outer stems, the sup- 

 port it received must have consisted of a system of " propping up." 



The thickest stem I have seen is 1 cm. broad, and belongs to 

 Sphenophylluyn myriophyllum, Crepin, but Zeiller figures a 

 branch of the same species of a slightly larger diameter.^ 



The internodes vary considerably in length, in the thickest 

 stems being little longer than broad; but they are on an average 

 from 1 cm. to 1'50 cm. long. The nodes are distinctly swollen, 

 having an acute ridge from which the leaves spring. 



The ribbing of the stems is usually very distinct, and the ribs 

 do not alternate at the nodes as in Calamites, but continue on 

 without interruption." 



The ramification of the stem is very sparse, only one branch 

 springs from a node,^ and the branches are usually separated by 

 a considerable number of internodes. In some cases the lateral 

 branches decrease in size upwards, in other cases they increase 

 considerably in diameter as they recede from the parent stem.'* 

 Interesting branching specimens of Sphenophyllum have been 

 figured by Germar,'^ Renault,^ Schenk,'' and Zeiller.^ 



1 Flore foss. Bassin houil. d. Valenciennes, PI. LXII., fig. 4. 



- It must be remembered that the "ribbed" Calamites are generally, if 

 not always, internal casts, whereas in ribbed S2ihenophyllum we have the 

 true outer surface of the stem. 



' The specimen of Sphenophyllum Schlotheimii given by Germar, Vers. 

 d. Sccnil: v. Wettin ti. Lohejun, fasc. ii., PL VI., fig. 1, seems to contradict 

 this statement, but the exact origination of the branches on this specimen 

 is not clearly seen. See also Schenk in " Richthofen's China," PI. XLIV., 

 fig. 1 (S. emarginatum). Here, however, the general rule seems to be 

 maintained. 



■* Zeiller, Flore foss. Bassin houil. d. Valenciennes, PI. LXII., fig, 4, 



^ Germar, I.e., fasc. ii., PI. IV., figs. 1 and 3 {Sphenophyllum 

 Schlotheimii). 



" Renault, Flore Joss. terr. houil, d. Comentry, PI. IV., figs. 6 and 7 

 (Sphenophyllum angustifolium). 



7 Schenk in "Richthofen's China," PI. XXXVIII., fig. \ {Sphenophyllum 

 Schlotheimii). 



« Zeiller, I.e., PL LXII., figs. 1 and 4; PL LXIIL, fig. 4 {Sphen, cwiei- 

 folium, var. saxifragafolmm). 



