Eucommia, Oliver, 1890

Ramírez-Arriaga, Elia, Prámparo, Mercedes B. & Martínez-Hernández, Enrique, 2014, Angiosperm pollen grains from the Cuayuca Formation (Late Eocene to Early Oligocene), Puebla, Mexico, Palaeontologia Electronica 102 (8), pp. 1-38 : 18

Eucommia pollen type

Figure 3.16

Material. Samples Pb-9138, Pb-8898, Pb-9340, Pb-8896, and Pb-9334, Palynology Laboratory, IGLUNAM.

Description. Monad pollen, isopolar, radiosymmetric, amb circular, subprolate. Tricolporoidate, with two large colpi: one measuring 24 P m long and a smaller one 17.6 µm long. Exine atectate, 0.8 – 1 µm thick, psilate.

Dimensions. Equatorial diameter 17–30 µm, polar diameter 22–35 µm, 13 specimens measured, five specimens measured.

Comparison. Eucommia sp. from the Cuayuca Formation has similar dimensions to E.? leopoldae ( Frederiksen et al., 1983) and the Eucommia type ( Frederiksen, 1988), but differs from both because they are tricolporate whereas the Eucommia herein described is distinctively tricolporoidate as seen in the Eucommia described by Erdtman (1972). It is also similar to Eucommia cf. E. ulmoides illustrated by Leopold (1974, plate 39, figure 13) and Wingate (1983, plate 2, figure 10).

Other occurrences. This genus was recorded in Mexico from the late Eocene to early Oligocene Pie de Vaca Formation, Puebla ( Martínez-Hernández and Ramírez-Arriaga, 1999); Oligocene of the San Gregorio Formation (Martínez-Hernández and Ramírez-Arriaga, 2006). U.S.A. – middle Eocene of Kisinger, Wyoming ( Leopold, 1974); Eocene, Nevada ( Wingate, 1983); early Eocene into middle Eocene, Gulf Coast ( Frederiksen, 1988); middle Eocene, Hominy Peak Formation, San Diego, California (Frederiksen, 1983); Eocene, Teton Range, Wyoming ( Love et al., 1978); late Oligocene of Florissant Formation, Colorado ( Leopold and Scott, 2001).