Pteroceltis knowltonii (Berry)

Na, Yuling, Blanchard, Jane & Wang, Hongshan, 2019, Fruits, seeds and flowers from the Puryear clay pit (middle Eocene Cockfield Formation), western Tennessee, USA, Palaeontologia Electronica (a 49) 23 (3), pp. 1-57 : 13

Pteroceltis knowltonii (Berry) Manchester, Chen, Lu and Uemura, 2009

Figure 18

1916 Dodonaea knowltoni Berry 1916, p. 271 , pl. 64,

fig. 3.

Description. Fruit broadly winged, consisting of a central, asymmetric, globose endocarp, and two wings with radiating striations; overall fruit size (including wings) 1.5–2 cm long and 2–2.3 cm wide; endocarp ca. 5 mm in diameter; two wings of different sizes, with small wing 3–5 mm wide and large wing 5–7.5 mm wide (measured in the direction parallel to striations). Styles two, persistent. Stipe short, 2 mm long and 0.5 mm wide.

Number of specimens examined. 6. UF15820- 029089, 055902, 055903, 055904, 059206, 059397.

Remarks. The genus Pteroceltis has only one extant species, Pteroceltis tatarinowii Maximowicz. This species is a tree of temperate regions of northern to south-central China and Mongolia. Modern Pteroceltis fruits consist of a globose endocarp, two finely striate lateral wings, and persistent perianth and style (Fu et al., 2003; Manchester et al., 2009). The characters of the six Puryear specimens are consistent with those of the modern fruits except that pedicels and persistent perianth are not observed.

Berry (1916b; p. 271, pl. 64, figure 3) described a fruit from the Puryear clay pit, Tennessee, and assigned this specimen to Dodonaea knowltoni . Manchester et al. (2009, p. 18, figure 17) emended it to Pteroceltis knowltonii . The specimen illustrated by Berry (1916b) shows a pedicel which does not show in the image of the same specimen in Manchester et al. (2009, p. 17, figure 17).

Pteroceltis fossil fruits have been described from the middle Eocene of Republic, Washington, USA (Pigg and Wehr, 2002), the late Oligocene of Germany (Manchester, 1989), and the Neogene of Korea and Japan (Oishi and Huzioka, 1942). However, Manchester et al. (2009) suggested that the Neogene records of this genus from Korea and Japan (Oishi and Huzioka, 1942) need to be reexamined to confirm or reject its assignment to Pteroceltis (Manchester et al., 2009). Other reports of this genus are based on leaves from Tennessee, USA ( Berry 1916b, p. 270, pl. 38, figure 2) and the Miocene of China (Sun et al., 1999, pl. 6, figure 4).

Figures

FIGURE 18. Pteroceltis knowltonii (Berry) Manchester, Chen, Lu and Uemura, 2009: 1-2) UF15820-029089, 029089', part and counterpart of specimen showing the short stipe (s). Scale bar equals 5 mm; 3) UF15820-055903, specimen showing cordate base, stipe (s) at the base, two styles at the distal end (indicated by arrows), and asymmetric fruit body and wings of different sizes. Scale bar equals 3 mm; 4-5) UF15820-055902, 055902', part and counterpart of specimen showing stipe (s) at the base and two styles at the distal end (indicated by the arrows). Scale bar equals 4 mm; 6) UF15820-059397, specimen showing stipe (s). Scale bar equals 4 mm.