464 



BENNETTITALES 



[CH. 



terminal strobili an indication of a primitive dichasium is afforded 

 by the occurrence of an aborted bud in a stem of Dioon edule 

 described by South and Compton 1 ; but in the habit of the stem 

 Wielandiella is far removed from any recent Cycadean type. 

 The microsporophylls are smaller and simpler than in Williamsonia 

 or Cycadeoidea and the foliage-leaves are of the Anomozamites type 

 (cf. fig. 615). 



Wielandiella angustifolia Nathorst. 



. In an account of this species in 1902 Nathorst described two 

 types of strobilus, male and female, but a re-investigation of the 

 material led to a modification of the earlier conclusions. The 



FIG. 567. Wielandiella angustifolia. Branched stem and receptacle. 

 (After Nathorst.) 



stem is slender, rarely exceeding 1-5 cm. in breadth, repeatedly 

 branched as a dichasial system with a fertile shoot in the forks 

 formed by the equal and widely divergent branches. Nathorst's 

 restoration, as he points out, may exaggerate the regularity of 

 the branching, but an examination of the original specimens in 

 the Stockholm Museum convinced me that the habit represented 

 in fig. 566 is substantially correct. The method of branching is 

 similar to that in the inflorescences of Gnetalean plants and 

 recalls some Gleichenia fronds. The surface of the thicker pieces 

 of stem shows fine longitudinal striae, while transverse striations 

 like those on the axis of a Heterangium frond characterise the 

 1 South and Compton (08) p. 225, fig. 36. 



