Figure 4 in Two new species of megasporangiate Sigillariostrobus Schimper (Sigillariostrobaceae) fructifications from the British Coal Measures

Figure 4. Sigillariostrobus barkeri sp. nov. No. 1971.I28, Barker collection, Sheffield City Museum, from the shales above the Shafton Coal, Brierly Colliery, Yorkshire (top of the Similis-Pulchra Zone, Bolsovian, Moscovian). (a) The remains of the cone showing the arrangement of the megaspores (scale bar 10 mm). (b) Camera lucida drawing of the cone in (a) (scale bar 10 mm). (c) Macerated in situ megaspore assigned to Tuberculatisporites mamillarius (Bartlett) Potonié and Kremp (scale bar 500 µm). (d) Contact face of the in situ megaspore (scale bar 150 µm). (e) Apiculi on the distal surface of the in situ megaspore (scale bar 10 µm). Figure previously published by Thomas (1980).