Aquatifolia fluitans Wang and Dilcher, 2006b

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 : 8

Aquatifolia fluitans Wang and Dilcher, 2006b

Figure 5.1-2

Description. Leaf shape wide ovate (length/width ratio 1.2:1) to very wide ovate ( L / W ratio 1:1 or less). Leaf base strongly cordate, with basal lobes overlapping or wide obtuse. Observed petiole length 28 mm long and 1.5 mm wide, containing a spherical float at a distance of ca. 10 mm from the leaf base (measured from the center of the spherical float to the leaf base). Float present on the petiole, spherical, sometimes appearing to be bilobed, or fusiform with some fine reticulate venation. Leaf margin entire, crenate, or strongly crenate. Typically, three veins entering a tooth with one medial vein perpendicular to the leaf margin and two flanking lateral veins (tertiary or quaternary) running along the margin before joining the medial vein. Primary venation is actinodromous or basal actinodromous; course of primary veins sinuous or straight; typically, one medial and four lateral primary veins (in two pairs) present in one leaf lamina. Primary veins and lateral secondary veins may fork up to three to four times, and adjacent branches join to form five ‐ to six ‐ sided elongate meshes oriented perpendicular to the leaf margin. All lateral primary veins and exmedial branches of lateral primary veins apically curved. Veins of higher order (tertiary or quaternary) orthogonally reticulate, forming quadrangular or pentagonal small meshes within those meshes formed by primary and secondary veins. Near the leaf margin, the veins dichotomize into veins of tertiary or quaternary order to form anastomosing loops from which arise one medial and two lateral veins that enter the tooth. Quinternary veins also orthogonally reticulate, forming the smallest polygonal meshes.

Number of specimens examined. 75.

Specimens illustrated. UF 15706-8263, 8263′ ( Figure 5.1 ); 24120 ( Figure 5.2 ).

Occurrences. Hoisington III locality, Kansas.

Remarks. Two specimens from Wang and Dilcher (2006b) are illustrated in this report. Figure 5.1 is the holotype specimen of Aquatifolia fluitans , showing the spherical float on the petiole. Figure 5.2 is a paratype specimen showing actinodromous primary venation and ovate leaf shape.

Figures

FIGURE 5. 1-2, Aquatifolia fluitans Wang and Dilcher 2006b, UF15706-8263′, leaf showing the spherical float on the petiole (1) and UF15706-24120, leaf showing cordate base and thin high order venation (2). Scale bars equal 5 mm. 3-4, Brasenites kansense Wang and Dilcher, 2006b, UF15706-14806, specimen (3) and line drawing (4) to show suborbiculate leaf shape, entire leaf margin, peltate central base, major primary veins. Scale bars equal 1 cm.