Pagiophyllum, HEER, 1881

Mendes, Mário Miguel, Dinis, Pedro & Kvaček, Jiří, 2018, Some Conifers From The Early Cretaceous (Late Aptian - Early Albian) Of Catefica, Lusitanian Basin, Western Portugal, Fossil Imprint 74 (3 - 4), pp. 317-326 : 321

Pagiophyllum sp.

Text-fig. 4h, i

D e s c r i p t i o n. The fragmentary shoot specimens consist of long, slender leaves arranged helically along unbranched axes ( Text-fig. 4h ). The leaves are up to 3 mm long and 0.6 mm wide. Their leaf cushion is narrowly elongate. They represent a continuation of a basal part of the leaf, without any particular broadened part ( Text-fig. 4h ). The abaxial surfaces are convex and keeled, whilst the adaxial surfaces are concave. Leaf margins show tiny, regular teeth ( Text-fig. 4i ). Leaves hypostomatic, stomata lack papillae.

D i s c u s s i o n. This taxon shows helically arranged leaves with stomata lacking papillae. It provides completely different characteristics than the first described group of conifers belonging to the Cheirolepidiaceae . Its stomata do not show any papillae. This type of foliage with falcate, helically arranged leaves may indicate Cupressaceae s.l., but its stomata are not arranged in bands. Due to its fragmentary preservation, the material is left in open nomenclature and its systematic affinity remains questionable. Additional studies should provide more details to its more precise identification.

Figures

Text-fig. 4. SEM micrographs of two types of conifers from the Early Cretaceous mesofossil flora of Catefica, Portugal. (a) Leafy twig of Watsoniocladus cf. virginiensis with opposite-decussate leaves showing convex, keeled, abaxial surface and concave, unkeeled, adaxial surface (P0127, sample Catefica 316). (b), (c) Details of the leaf apex showing amphistomatic abaxial and adaxial surfaces (P0127, sample Catefica 316). (d) Detail of stomata surrounded by a raised rim with finger-like outer papillae showing star-shaped stomatal apertures (arrows) (P0127, sample Catefica 316). (e), (f) Leafy twig of Watsoniocladus cf. virginiensis showing hook-shaped leaves in outline (P0129, sample Catefica 317). (g) Detail of the abaxial surface showing stomata arranged in ill-defined rows (P0129, sample Catefica 317). (h) Leafy twig of Pagiophyllum sp. showing convex, keeled, abaxial surface and concave, unkeeled, adaxial surface (P0126, sample Catefica 318). (i) Detail of the abaxial leaf surface showing serrate margin and scattered stomata (P0126, sample Catefica 318). Scale bars = 1 mm (a, e, f, h); 100 μm (b, c, g, i); 50 μm (d).