ROSALES von Berchtold and Presl, 1820

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 : 20-23

Order ROSALES von Berchtold and Presl, 1820 Family RHAMNACEAE de Jussieu, 1789 “ Solanites ” pusillus Berry, 1930

( Figures 17 , 18 )

* 1930 Solanites pusillus Berry , p. 132, pl. 48, figs. 21-23.

v* 2010 Solanites pusillus Berry ; Martínez-Millán, p. 167-174, figs. 3.3 D-L, 3.4 A-F.

Description. Flower 5-merous, 8–10 mm in diameter; ovary inferior. Five sepals alternating with five petals; sepals equilateral or isosceles-triangular in shape, 2.5–3 mm long and 2.5–3 mm wide at the base. Petals thin, ca 3 mm long and 1–2 mm wide, often not well preserved. Sepals and petals in two separate whorls; a midvein present in each sepal, extending across the rim to the hypanthium; trichomes present on sepals, petals, and hypanthium. Well-developed hypanthium circular in vertical view (3.5–4.5 mm in diameter) and obtriangular in lateral view (3.5 mm long and 3.5 mm wide at the top); a compressed distal rim ca 0.8–1 mm thick present. Stamens opposite the petals. Pedicel ca 1 mm long and 0.5 mm wide.

Number of specimens examined. 6. UF15737- 008226, 049566, 049568; UF15738-008214.

Remarks. The hypanthium is formed by the fusion of the bases of the sepals. This is indicated by the observation that the midveins of the sepals extend across the hypanthium rim nearly to the center of the floral cup in vertically preserved flowers ( Figure 18.2 ). That the stamens are opposite the petals is indicated by the fact that two filaments are located between two sepals ( Figure 18.2 ). See Table 4 for a comparison of Solanites pusillus with other similar Claiborne floral types.

Martínez-Millán (2010) and Millan and Crepet (2014) observed that the combination of characters including: 5-merous flowers with a cupulate hypanthium ending in a thick floral rim; triangular sepals with a prominent midvein or keel; thin, clawed cupulate petals alternating with the sepals; and stamens opposite the petals is found in the Rhamnaceae , rather than Solanaceae as suggested by Berry (1916b, 1930). They also noted that tricolporate pollen with a rugulate to striate-rugulate exine (pollen extracted from UF15737-049566; Figure 17.4 ) is also consistent with pollen of the Rhamnaceae .

Figures

FIGURE 17. “Solanites” pusillus Berry, 1930: 1) UF15737-049568. Vertically compressed flower showing five triangular sepals (s) alternating with petals (p, only three are visible), and a floral cup at the center. Scale bar equals 1 mm; 2) UF15737-049568'. Counterpart of Figure 17.1 showing sepals and membranaceous petals with conspicuous venation. Scale bar equals 1 mm; 3) UF15737-008226. A laterally compressed flower showing an obtriangular hypanthium with an inferior ovary (o), a short pedicel (indicated by arrow), and three sepals (s), and three petals (p). Scale bar equals 1 mm; 4) UF15737-049566. Vertically compressed flower showing a circular floral cup (dark concentric rings) and five triangular sepals alternating with five petals. Scale bar equals 1 mm; 5) UF15737-049566'. Counterpart of Figure 17.4 showing sepals alternating with petals, and a floral cup with radiating veins. Note the center hole resulted from vertical compression of the pedicel. Scale bar equals 1 mm; 6) Enlargement of Figure 17.2 to show venation of sepal (s) and petal (p). Scale bar equals 0.5 mm.

FIGURE 18. “Solanites” pusillus Berry, 1930: 1) UF15738-008214. Vertically compressed flower showing four sepals. Note two filaments (f) between two adjacent sepals (s) indicated by arrows. Scale bar equals 1 mm; 2) UF15738- 008214'. Counterpart of Figure 18.1 showing five sepals and the radiating veins on the hypanthium extending to the sepals (indicated by arrow). Scale bar equals 1 mm.