Jarzenia kanbrasota, Wang and Dilcher, 2009

Wang, Hongshan & Dilcher, David L., 2018, Early Cretaceous angiosperm leaves from the Dakota Formation, Hoisington III locality, Kansas, USA, Palaeontologia Electronica (34 A) 21 (3), pp. 1-49 : 18

Jarzenia kanbrasota Wang and Dilcher, 2009

Figure 11.1

Description. Lamina elliptic, L / W 2.5, 3.5 to 4 cm wide and 9 to 10 cm long (estimated length). Apex missing. Base acute, decurrent. Margin entire. Petiole missing. Primary venation pinnate; primary vein stout, multi-stranded, course straight. Secondary venation brochidodromous; secondary vein moderate relative to primary vein.>eight pairs per lamina, opposite to subopposite, decurrent; spacing irregular; angle of divergence narrow acute (<45º), uniformly curved to join exmedial branches of superadjacent secondary veins to form one series of loops. Intersecondary veins present, course simple. Tertiary veins not well preserved.

Number of specimens examined. 2.

Specimens illustrated. UF 15706-3171 ( Figure 11.1 ).

Occurrences. Hoisington III locality, Kansas and Courtland I locality, Minnesota.

Remarks. Jarzenia kanbrasota differs from Setterholmia rotundifolia (Lesquereux) Wang and Dilcher, 2009 in that J. kanbrasota has oblanceolate or narrow obovate shape, more cuneate leaf base, lowest one or two pairs of secondary veins originating at more acute angles than those above, not well defined intercostal regions, less percurrent tertiary veins, and the absence of glands on leaf lamina and veins. Jarzenia kanbrasota is very common at several localities of the Dakota Formation in Kansas and Nebraska based upon observation of specimens stored in the Paleobotany and Palynology collection at the Florida Museum of Natural History.

Figures

FIGURE 11. 1, Jarzenia kanbrasota Wang and Dilcher, 2009, UF15706-3171, showing elliptic leaf shape and secondary venation. Scale bar equals 1 cm. 2, Liriophyllum kansense Dilcher and Crane, 1984, UF15826-3188, showing deeply lobed leaf, long petiole, and secondary venation. Scale bar equals 1 cm. 3, Credneria cyclophylla (Heer) Wang and Dilcher, 2009, UF15706-14821, leaf showing craspedodromous venation. Note all secondary veins and their exmedial branches terminating on leaf margin, resulting in a wavy appearance of leaf margin. Scale bar equals 1 cm.