Zizyphus” fibrillosus (LESQUEREUX) LESQUEREUX

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 : 175-176

“ Zizyphus” fibrillosus (LESQUEREUX) LESQUEREUX

This species resembles some Rhamnaceae in 1) the closely spaced percurrent tertiaries, and 2) in the acrodromous pattern with numerous agrophics. However, the first pattern, found in genera like Rhamnus , Karwinskia , Berchemia , is not generally linked with the second pattern in the same genera. When actinodromy occurs, for example in Ziziphus , Colubrina , etc., the tertiary venation is more irregular and not closely spaced percurrent. It therefore seems unlikely that this leaf belongs in an extant genus of the Rhamnaceae , and the assignment to Ziziphus is probably incorrect. The generic name for this species was also placed in quotation marks by Ellis et al. (2003), indicating that that they were not convinced that it represents extant Zizyphus .

Vitaceae

Brown (1962) confirmed the presence of the grape family by documenting a seed with the characteristic paired ventral infolds, which he assigned to Vitis sp. The dorsal side of the seed is not known. A silicified seed of Ampelocissus was also identified from the Paleocene of North Dakota ( Chen and Manchester 2007).

Reports of Vitaceae based on leaves have not been completely convincing. These include Ampelopsis acerifolia (reassigned to Archeampelos acerifolia (NEWBERRY) MCLVER et BASINGER, See Cercidiphyllaceae , above), Cissus marginata and (reassigned to Platanaceae as Platanites marginata ), Vitis lobata (KNOWLTON) R. W. BROWN (reassigned to Cucurbitaciphyllum lobatum , above). The leaf identified as Vitis olrikii HEER by Brown (1962) was separated from the Greenland species and given a new binomial, Dicotylophyllum hansonium PEPPE et HICKEY (2014) . Others that require additional study are Cissites rocklandensis R. W. BROWN , and Parthenocissus ursina R. W. BROWN. Cissites rocklandensis has a broadly ovate lamina with three asymmetrically and weakly developed lobes, with a rounded sinus between the middle lobe and each of the lateral lobes. This resembles the leaves of Gyrocarpus ( Hernandiaceae ) and Exbucklandia ( Hamamelidaceae ).

Ericaceae