Macginitiea 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 : 161

Macginitiea J. WOLFE et WEHR

Leaves of the extinct genus Macginitiea are distinguished from those of extant Platanus by a narrower angle between adjacent primary veins, and a chevron pattern formed by interconnected secondary veins between adjacent primaries in the lower part of the lamina ( Manchester 1986, Wolfe and Wehr 1987), and are consistently associated with infructescences that differ from those of modern Platanaceae by the lack of dispersal hairs on the fruits ( Macginicarpa ) and stamens dispersed in floral units of five, adhering by their elongate connectives ( Macginistemon ; Manchester 1978). The stamen units illustrated as “calyx of a flower” by Brown (1962, pl. 68, fig. 27–29) correspond to Macginistemon mikanoides (MACGINITIE) MANCHESTER (1978), and probably derive from the same trees as Macginitiea .

Brown (1962) considered both 3- and 5-lobed leaves to represent a single species, Platanus nobilis NEWBERRY. However , it seems probable that the 5- and 3-lobed populations represent distinct species, because many localities are greatly dominated by, or exclusively represented by, one kind or the other. Trilobate leaves are lacking from some of the other species of Macginitiea , e.g., M. angustiloba and M. whitneyi from the Eocene of California and Oregon ( Manchester 1986).