Gleditsia, Linnaeus, 1742

Blanchard, J, Wang, H & Dilcher, D, 2016, Fruits, seeds and flowers from the Bovay and Bolden clay pits (early Eocene Tallahatta Formation, Claiborne Group), northern Mississippi, USA, Palaeontologia Electronica 19 (3), pp. 1-59 : 12-15

Genus GLEDITSIA Linnaeus, 1742 cf. Gleditsia? mississippiensis Berry, 1916b

( Figure 9 )

* 1916 Cassia mississippiensis Berry , p. 235; pl. 51, figs. 10, 11.

* 1930 Gleditsia? mississippiensis (Berry) Berry , p. 82, pl. 50, figs. 2-4.

v* 1992 cf. Gleditsia? mississippiensis Herendeen , p. 128-129, figs. 225-230.

Description. “The fruits are 1.5–1.9 cm long; 0.9– 1.0 cm wide; stipitate, 2–5 mm long; round, oblong or ovate with rounded apex and base; valves coriaceous, possibly thickened over seed chamber; seed possibly one; calyx lobes five, rounded, reflexed” (Herendeen, 1992, p. 128-129; see also Wang et al., 2013).

Number of specimens examined. 1. UF15738- 008791.

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Remarks. This specimen was described by Herendeen (1992, p. 128-129, figures 229, 230). He considered it to be similar to fruits described by Berry (1916b, 1930) as Cassia mississippiensis and Gleditsia? mississippiensis but differing in size, shape, and calyx structure.

“Short, broad winged fruit”

( Figure 10 )

v* 1992 “Short, broad winged fruit”, Herendeen, p. 129, figs. 231-238.

Description. “The fruits are 3.0–6.0+ cm long, 1.6–3.2 cm wide; apex rounded to attenuate; base abruptly rounded to attenuate; fruits stipitate, 5 mm long; margins straight to slightly constricted; nonvascularized wing on placental suture, up to 2 mm wide; seeds 1–2, possibly round; valves thin and membranous, venous; orientation of major veins variable, from approximately perpendicular to oblique; calyx open, radially symmetrical” (Herendeen, 1992, p. 129).

Number of specimens examined. 4. UF15737- 008279; UF15738-008790.

Remarks. Herendeen (1992) described eight specimens from the Puryear locality, Tennessee, and Bolden and Bovay localities, Mississippi. The two specimens illustrated in Figure 10 were also illustrated by Herendeen (1992, figures 236, 237). He did not feel that there was sufficient detail to allow assignment of these fruits to a specific taxon within the Fabaceae . Herendeen (1992) noted that the open radially symmetrical calyx is suggestive of caesalpinioid, mimosoid, or basal papilionoid ( Sophoreae ) genera, and that the bilateral symmetry of some papilionoid groups may be difficult to perceive in a lateral view of a compressed calyx.

Claiborne Fabaceae Floral Type 1

( Figure 11 )

Description. Laterally preserved flower 2 cm long. Pedicel short, broken. Calyx rounded, ca 3 mm long and 3 mm wide. The three visible sepals connate except for ca 1 mm at apices. Petals thin, not well preserved, at least two, one of which is longer. Expanding ovary present, 10 mm long and 2.5 mm wide, with an apical style about 1.5 mm long. One stamen present; filament ca 9 mm long, anther 1.5 mm long.

Number of specimens examined. 1. UF15737- 059328.

Remarks. The presence of a standard petal on this specimen suggests that it probably represents a zygomorphic papilionoid flower. This type of flower has been reported from the middle Eocene localities of Tennessee ( Crepet, 1984; Crepet and Taylor, 1985; Friis and Crepet, 1987) and is often preserved with an expanding ovary ( Crepet and Taylor, 1985).

Claiborne Fabaceae Floral Type 2

( Figure 12 )

Description. Laterally compressed flower(s) 7–10 mm long and up to 7 mm wide at the widest point; ovary ca 2 mm long and 2.5 mm wide, tapering to a pedicel 5–5.5 mm long and 1 mm wide. One style present, 2 mm long. Stamens numerous, filaments 1 mm long, anthers 0.5 mm in diameter. Petal 1 mm long and 1 mm wide, with at least four fine veins, recurved. Number of sepals and petals unknown.

Number of specimens examined. 4. UF15738- 008215; UF15737-059252, 059312.

Remarks. This floral type differs from Protomimosoidea buchananensis in having numerous stamens with short filaments rather than 10 stamens with long filaments. It differs from Claiborne Fabaceae Floral Type 1 in not having a zygomorphic floral structure. Table 2 summarizes the differences among Claiborne Fabaceae Floral Types 1 and 2, Protomimosoidea buchananensis , and Claiborne Floral Types 17 and 18.

Figures

FIGURE 9. cf. Gleditsia? mississippiensis Berry, 1916b: 1-2) UF15738-008791, 008791'. Part and counterpart of a specimen showing stipe (s), calyx (c), calyx lobes (cl), and pod with rounded apex. Scale bar equals 2 mm.

FIGURE 10. "Short, broad winged fruit" (1-3) UF15737-008279: 1) Showing stipe (s), calyx (c), and pod with attenuate apex (a). Scale bar equals 5 mm; 2) Counterpart of UF15737-008279. Scale bar equals 5 mm; 3) Enlargement of Figure 10.2 to show valve venation. Scale bar equals 2 mm; 4) 15738-008790. Showing stipe (s), calyx (c), and pod with attenuate apex (a). Scale bar equals 5 mm.

FIGURE 11. Claiborne Fabaceae Floral Type 1, UF15737-059328. Laterally preserved flower showing a short pedicel (pd), calyx (c), 2 petals (pt), standard petal (sp), expanding ovary (o) with an apical style (st), and a stamen with a filament (f) and an anther (a). Scale bar equals 2 mm.

FIGURE 12. Claiborne Fabaceae Floral Type 2: 1-2) UF15738-008215, 008215'. Part and counterpart of a laterally preserved flower showing style (s) and a pedicel (p). Scale bars equal 2 mm; 3) Enlargement of Figure 12.2 to show anthers (a), filaments (f), and calyx (c). Scale bar equals 1 mm; 4-5) UF15737-059312, 059312'. Part and counterpart of a laterally preserved flower showing a petal (indicated by arrows) and stamens above. Scale bar equals 2 mm; 6) UF15737-059252. A laterally compressed, immature flower showing a style (s). Scale bar equals 2 mm.