Acer sp.

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 : 175

Acer sp.

Some of the samaras that were called Acer sp. by Brown (1962, especially pl. 46, figs 9, 10) appear to be genuine examples of that genus, having an oblique proximal scar indicating schizocarpic separation—one of the diagnostic features of Acer . Similar Acer -like samaras were recognized by Crane et al. (1990) from Almont, North Dakota, although corresponding foliage was not recognized.

Acer fragilis KNOWLTON 1917 was transferred to Cissites panduratus KNOWLTON by Wolfe and Tanai (1987).

Acer newberryi R. W. BROWN was revised as Dicotylophyllum trilobum (NEWBERRY) by Wolfe and Tanai (1987). “The only criterion on which the foliage just cited has been placed in Acer is a trifoliate condition. The leaflets lack bifurcating secondary veins that brace dental sinuses (as are present in Negundo ); the dental sinuses are braced by an apically directed external secondary vein that originates from a secondary vein subjacent to the sinus, a morphology unknown in Acer . Although the tertiary veins are A-A [referring to Hickey’s (1973) terminology, i.e., convexpercurrent; forming acute angles with the sub- and superadjacent secondary veins], they are more closely spaced than in Acer and have a “stringy” appearance. No extant family combines such characters.” ( Wolfe and Tanai 1987, p. 212).

Leguminosae

Leguminosites coloradensis KNOWLTON. The genus Leguminosites was based on seeds from the London Clay that are not of leguminous affinity ( Wang 2012). Instead, this species should perhaps be placed in the genus Leguminocarpum DOTZLER. However, Brown (1962, p. 74) expressed uncertainty whether these fruits represent pods of legumes, “or perhaps some other family of plants such as the Bignoniaceae .”

“ Robinia ” wardii (KNOWLTON) WARD. These pods from the Fort Union Formation differ from the type material of Robinia wardii from Eocene of Yellowstone National Park and therefore require a different specific epithet. They are clearly legume fruits, but the generic assignment is in need of revision (Herendeen, pers. comm. 2014).

? Rhamnaceae

The presence of Rhamnaceae in these floras is not fully proven, but some of the leaves, e.g. Rhamnus cleburnii LESQUEREUX and Zizyphus fibrillosus (LESQUEREUX) LESQUEREUX have distinctive venation that is consistent with some extant Rhamnaceae . “ Rhamnus” geowandrewsii WATT (syn. Rhamnus hirsuta R. W. BROWN ), does not appear to represent Rhamnaceae and is treated here among insertae sedis.