Macginitiea gracilis (LESQUEREUX) J. WOLFE et WEHR

Manchester, Steven R., 2014, Revisions To Roland Brown’S North American Paleocene Flora, Acta Musei Nationalis Pragae Series B 70 (3 - 4), pp. 153-210 : 163

Macginitiea gracilis (LESQUEREUX) J. WOLFE et WEHR

Text-figs 4.1–4.3

Macginitiea gracilis is the type species of Macginitiea as designated by Wolfe and Wehr (1987), based on a deeply 5-lobed specimen collected by Hayden from Bridgers Pass, Wyoming from a fine sandstone of probable Maastrichtian age. The type specimen ( Text-fig. 4.1 ) was initially named Liquidambar gracilis ( Lesquereux 1872) and later figured as Aralia? gracilis LESQUEREUX (1878 , pl. 39, fig. 1). Wolfe and Wehr (1987) applied this same epithet to specimens from the Eocene of Republic, Washington. Among the numerous specimens from the Clarkforkian Killpecker Creek flora at Rock Springs, Wyoming ( Wilf 2002), all are deeply five-lobed, while those from the Tiffanian Joffre Bridge site, Alberta (discussed below; Pigg and Stockey 1991) are three-lobed. Among the many Paleocene leaves that Brown (1962) included as Platanus nobilis NEWBERRY , those with five prominent digitate lobes are now treated as M. gracilis , while those with three lobes are treated as Macginitiea nobilis . The leaves vary from entire to serrate, have palinactinodromous venation, and usually long petioles with expanded bases.

Figures

Text-fig. 4. Platanaceae 1–3. Macginitiea gracilis (LESQUEREUX) J. WOLFE et WEHR leaves and associated reproductive structures 1. Holotype of Aralia gracilis LESQUEREUX from Bridger Pass, Wyoming, USNM 330. 2. Specimen showing the typical configuration of five lobes, Killpecker Creek flora, Wyoming. UF 18126-13242. 3. Silicified M. gracilis leaf from Almont, North Dakota; arrow indicates adjacent Macginicarpa infructescence, UF 15722-29202a. 4. Macginicarpa infructescence from Almont, UF15722-35493. 5. Platananthus sp., Almont, UF 15722-62019. 6. Macginicarpa glabra MANCHESTER infructescence, enlarged from fig. 3, UF 15722-29202b. Specimens in figs 3-6 collected and donated by John Curtis. Scales = 1 cm. Images 3–6 light-dark inverted.