Crassidenticulum decurrens (Lesquereux) Upchurch and Dilcher, 1990

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 : 6

Crassidenticulum decurrens (Lesquereux) Upchurch and Dilcher, 1990

Figure 4.1

*1892 Celastrophyllum decurrens Lesquereux , p. 172, plate 36, figure 1.

Description. Leaflet margin toothed. Primary venation pinnate; primary vein massive, course straight. Secondary venation mixed craspedodromous (most of the secondary veins terminating at the margin and the rest brochidodromous); secondary veins thin, angle of divergence wide acute at 80 °; course of secondary veins irregular, straight, slightly curved or recurved; secondary veins densely arranged, 5 to 10 pairs per cm at middle portion of lamina, spacing irregular; intersecondary veins common. Veins of higher order not observed.

Number of specimens examined. 2.

Specimens illustrated. UF 15706-24648 ( Figure 4.1 ).

Occurrences. Rose Creek locality, Nebraska; Braun Ranch and Hoisington III localities, Kansas.

Remarks. The venation pattern and tooth type of the two leaflet fragments are consistent with those described by Upchurch and Dilcher (1990) and Wang and Dilcher (2006a). Therefore, we interpret this specimen as conspecific and the blade as a leaflet. The chloranthoid tooth type (tooth with a prominent, often thickened gland, a medial vein and a pair of accessory veins that run along the tooth margin and fuse with the gland) and the secondary venation pattern of Crassidenticulum show its closest similarities with extant Chloranthaceae (Upchurch and Dilcher 1990) .

Figures

FIGURE 4. 1, Crassidenticulum decurrens (Lesquereux) Upchurch and Dilcher, 1990, UF15706-24648, fragment of leaf lamina. Note fine teeth on margin (indicated by arrow). Scale bar equals 2 mm. 2, Crassidenticulum trilobum Dilcher and Wang, 2006a, UF15706-24677, a trilobed leaf. Note thin and long petiole. Scale bar equals 1 cm. 3-4, cf. Crassidenticulum trilobum Dilcher and Wang, 2006a, UF15706-24684, a five lobed leaf (scale bar equals 1 cm) (3) and an enlargement of Figure 4.3 to show decurrent lamina tissue between two adjacent lobes (indicated by arrow) (scale bar equals 1 mm) (4).