Download the full-sized PDF of Cobbania corrugata (Lesquereux) comb. nov. (Araceae): A floating aquatic aroid from the Upper Cretaceous of western North AmericaDownload the full-sized PDF



Permanent link (DOI):


Export to: EndNote  |  Zotero  |  Mendeley


This file is in the following communities:

Biological Sciences, Department of


This file is in the following collections:

Journal Articles (Biological Sciences)

Cobbania corrugata (Lesquereux) comb. nov. (Araceae): A floating aquatic aroid from the Upper Cretaceous of western North America Open Access


Author or creator
Stockey, R.A.
Rothwell, G.W.
Johnson, K.
Additional contributors
Dinosaur Park
fossil plants
Type of item
Journal Article (Published)
The fossil record of aquatic flowering plants broadens our understanding of their former diversity and origins from terrestrial ancestors. This paper describes a floating aquatic monocot from 71 whole plants and several isolated leaf fragments from Upper Cretaceous oxbow lake sediments in the Dinosaur Park Formation, Alberta, Canada. The new material is represented by rosettes of leaves and roots attached to short stems that are interconnected by stolons and corresponds to the fossil aroid originally described as Pistia corrugata Lesquereux. Up to six plants have been found interconnected on a single slab suggesting that these plants grew in extensive floating mats covering lakes and calm stretches of rivers. Stems have up to six leaves and large numbers of branched aquatic roots. The leaf is trumpet-shaped with an elongate clasping petiole, large aerenchymatous base, and a nearly circular blade rim. Leaf bases are often filled with sediment giving the leaf the appearance of having a basal pouch. Petioles have 6–9 veins that divide into an upper and lower set, and veins converge at an apical notch. A submarginal collective vein and at least two marginal veins with branching veins form the leaf rim. A series of dichotomizing and anastomosing veins characterize the adaxial leaf surface. Tertiary and quaternary veins form polygonal areolae. Leaf surfaces are covered in trichomes that, like those in Pistia stratiotes, probably aided in buoyancy. A reconstruction of the plant is presented. Based on unique leaf morphology, these fossil plants are clearly not assignable to the genus Pistia and are described as Cobbania corrugata (Lesquereux) Stockey, Rothwell et Johnson gen. et comb. nov. Recent systematic analyses using molecular characters resolve two separate origins of floating aquatic aroids included in the duckweeds and the genus Pistia. This new fossil genus increases our understanding of colonization of aquatic habitats by revealing a third possible origin of the floating aquatic habit within Araceae.
Date created
License information
This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.
Citation for previous publication
RA Stockey, GW Rothwell and K Johnson. "Cobbania corrugata (Lesquereux) comb. nov. (Araceae): A floating aquatic aroid from the Upper Cretaceous of western North America." American Journal of Botany 94 (2007): 609-624. DOI: 10.3732/ajb.94.4.609
Link to related item

File Details

Date Uploaded
Date Modified
Audit Status
Audits have not yet been run on this file.
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 1792969
Last modified: 2015:10:12 10:34:18-06:00
Filename: AJOB_94_2007_609.pdf
Original checksum: 998074a386d42ee95bd251fb0c26c77f
Well formed: true
Valid: true
File title: abot-94-04-03 609..624
Page count: 16
Activity of users you follow
User Activity Date