Scolecopteris cf. elegans Zenker, 1837

Galtier, Jean, Ronchi, Ausonio & Broutin, Jean, 2011, Early Permian silicified floras from the Perdasdefogu Basin (SE Sardinia): comparison and bio-chronostratigraphic correlation with the floras of the Autun Basin (Massif central, France), Geodiversitas 33 (1), pp. 43-69 : 57-58

Scolecopteris cf. elegans Zenker, 1837 ( Fig. 8B )

This oblique transverse section of one pinnule also shows a lamina with palisade and spongy parenchyma but thin, more than 2 mm long, lateral extensions

FIG. 8. — Silicified plants from the Permian of Sardinia: A, Pecop- teris sp., transverse section of one vegetative pinnule showing thick lamina with palisade and aerenchyma mesophyll.Note the hair (arrow) attached near the lower extremity (SAR15B1T02); B, Scolecopteris cf. elegans Zenker , oblique transverse section

of one pinnule showing two synangia attached on the left side. Note the thick lamina similar to that of Pecopteris sp. (A) but long thin pinnule extension on the right (SAR40C01); C, Scolecopteris cf. parvifolia Millay , part of a longitudinal section of one pinnule passing through several synangia. Note the relatively thin lamina, synangia borne on a short vascularised pedicel and solid tips of sporangia (SAR56AT02); D, E, Scolecopteris cf. alta Millay ; D, longitudinal section of a synangium showing the characteristic central column; E, transverse sections of synangia, the one above is through the basal part of the synangium, the other is through the distal region showing only four dehiscent sporangia (SAR01C2B02). Scale bars: 0.5 mm.

of the lamina enclosing the synangia. These fertile pinnules correspond to those shown in paradermal section on Figure 7F and there is good evidence that they were borne by a rachis of the Stewartiopteris sp. 2 type ( Fig. 7D ). Despite strong similarities in sporangia and synangiate organization with Scolecopteris oliveri , the sizes of the pinnules (about 2 mm broad and 4-6 mm long), synangia and sporangia (less than 1 mm long) are smaller than those of S. oliveri , according to measurements given by Scott (1932). Moreover,the lateral pinnule extensions are much more pronounced than in S. oliveri ; in fact, this Sardinian Scolecopteris rather resembles the organization and size of fertile pinnules of S. elegans Zenker, 1837 from the Lower Permian of Saxony ( Barthel & Weiss 1997) or of S. minor Hoskins, 1926 from the Upper Pennsylvanian of Illinois which belong to the Scolecopteris minor group defined by Millay (1979; 1997).

Figures

FIG. 8. — Silicified plants from the Permian of Sardinia:A, Pecop- teris sp., transverse section of one vegetative pinnule showing thick lamina with palisade and aerenchyma mesophyll.Note the hair (arrow) attached near the lower extremity (SAR15B1T02); B, Scolecopteris cf. elegans Zenker, oblique transverse section of one pinnule showing two synangia attached on the left side. Note the thick lamina similar to that of Pecopteris sp. (A) but long thin pinnule extension on the right (SAR40C01); C, Scolecopteris cf. parvifolia Millay, part of a longitudinal section of one pinnule passing through several synangia. Note the relatively thin lamina, synangia borne on a short vascularised pedicel and solid tips of sporangia (SAR56AT02); D, E, Scolecopteris cf. alta Millay; D, longitudinal section of a synangium showing the characteristic central column; E, transverse sections of synangia, the one above is through the basal part of the synangium, the other is through the distal region showing only four dehiscent sporangia (SAR01C2B02). Scale bars: 0.5 mm.

FIG. 7. — Silicified plants from the Permian of Sardinia:A, B, Psaronius sp.; A, part of the inner root mantle of a trunk,transverse section showing the small roots and interstitial tissue (SAR 13BB01); B, transverse section of one large free root of the outer zone; note the broad aerenchymatous cortex (SAR10A01); C, D, rachises of fronds borne by Psaronius; C, Stewartiopteris sp.1, rachis with a broad C-shaped xylem strand (arrows) and middle cortex with small lacunae (SAR59AT01); D, Stewartiopteris sp. 2., rachis with a different cortex bearing a probable third order one (R3) with fertile pinnule attached (SAR46B01); E, F, foliage of fronds borne by Psaronius; E, accumulation of fronds showing vegetative (above) and fertile pinnules (below) seen in transverse section (SAR40C1T01); F, part of a fertile pinna seen in paradermal section (SAR03A1T02). Scale bars: 2 mm.