Cobbania hickeyi Stockey, Rothwell et K.R.Johnson

Plant Fossil Names Registry Number: PFN001939

Act LSID: urn:lsid:plantfossilnames.org:act:1939

Authors: R. A. Stockey, G. W. Rothwell & K. R. Johnson

Rank: species

Genus: Cobbania Stockey, Rothwell et K.R.Johnson

Reference: Stockey, R. A., Rothwell, G. W. & Johnson, K. R. (2016): Evaluating relationship among floating aquatic monocots: A new species of Cobbania (Araceae) from the Upper Maastrichtian of South Dakota. – International Journal of Plant Sciences 177(8): 706–725., link

Page of description: 708

Illustrations or figures: figs 1–6

Types

Original diagnosis/description

Small rosettes of up to 5 leaves per plant borne on short stems 4–7 mm in diameter, connected by stolons, growing in large mats. Up to 5 stolons/stem, 3–5 mm in diameter, with central dark band of presumed vascular tissue. Floating branched aquatic roots 1–2 mm wide, at least 7 cm long, with central vascular zone up to 1 mm wide in largest roots; branch roots numerous, 0.1 mm wide, up to 20 mm long. Adventitious roots simple, unbranched, arising from stems of plantlets, 0.1 mm wide. Leaves 2.5–7.5 cm long (mean = 4.03 cm), 2.5–6.2 cm wide (mean = 4.45) in apical surface view with central oval, aerecnchymatous zone 1.7–3.2 cm and large rim 1–3 mm wide at leaf base, 9–16(20) mm wide at lateral margin. Leaf surface hirsute; trichome bases 150 μm in diameter. Petiole 1 cm long with up to 19 veins branching to form abaxial and adaxial series. One central and two lateral major abaxial veins pinnate with dichotomizing laterals. Lateral primary veins dichotomize to corm collective vein in rim and 3 or 4 submarginal veins; innermost widely spaced, branching at angles of 90° near leaf apex and 45°–60° near middle and base of leaf. Collective veins and fimbrial vein converge in and below apical notch.

Etymology

For Dr. Leo J. Hickey, Yale University, for his extensive work on Cretaceous and Paleogene floras of North America: a friend and mentor who never let us get away with anything.

Stratigraphy

Cretaceous, Upper Cretaceous, Maastrichtian
Hell Creek Formation, floral zone HC1, age 66.25–67 Ma

Locality

United States
DMNH locality 2703; "Licking Leaves", 45.6°N, 103.8°W; UTM Zone 13 597500E 5048826N; Pine Spring 7.5ʹ Quad; northwest quarter of Section 27, Township 19N, Range 3E.