Late Devonian plants from Australia: the anatomically preserved flora from Barraba, New South Wales.

Conference (2008)

The proto-ovule Runcaria heinzelinii Stockmans 1968 emend. Gerrienne et al., 2004 (mid-Givetian, Belgium): Concept and epitypification.

in Review of Palaeobotany and Palynology (2007), 145(3-4), 321-323

The proto-ovule Runcaria heinzelinii Stockmans 1968 has been re-described and interpraed as a precursor of seed plants; its generico-specifica diagnosis has been emended [Gerrienne, P., Meyer-Berthaud, B ... [more ▼]

The proto-ovule Runcaria heinzelinii Stockmans 1968 has been re-described and interpraed as a precursor of seed plants; its generico-specifica diagnosis has been emended [Gerrienne, P., Meyer-Berthaud, B., Fairon-Demaret, M., Streel, M., Steemans, P. 2004. Runcaria, a Middle Devonian seed plant precursor. Science 306, 856-858.]. Here we define the concept of "proto-ovule" and designate an epitype to support the uninformative and poorly preserved holotype [Stockmans, F., 1968. Vegetaux mesodevoniens recoltes aux confins du Massif du Brabant (Belgique). Inst. Roy. Sci. Nat. Belg. Mem. 159, 1-49., Plate VII: 8a]. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

Givetian megaspores from Libya and Belgium

Conference (2007)

Embryophytes on land: the early steps.

Conference (2007)

Lectotypification of the Famennian pre-ovule Condrusia rumex Stockmans, 1948

in Review of Palaeobotany and Palynology (2006), 142(3-4), 161-164

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing ... [more ▼]

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing" axes. Various interpretations have been given to this intriguing structure, ranging from a spore-bearing organ to a fern prothallus but recent investigations consider Condrusia to be an ovulate structures produced by early seed plants. The genus Condrusia includes 3 species: C rumex Stockmans, C. minor Stockmans and C. brevis Petrosjan. C rumex was described by Stockmans in 1948, who provided a diagnosis and illustrations, but failed to designate a holotype. We are currently reinvestigating the genus and we here designate and illustrate a lectotype for the genus and species C. rumex. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

An exceptional specimen of the early land plant Cooksonia paranensis, and a hypothesis on the life cycle of the earliest eutracheophytes

in Review of Palaeobotany and Palynology (2006), 142(3-4), 123-130

An exceptionally large specimen of the early land plant Cooksonia paranensis Gerrienne et al. has been discovered from the type locality (Jackson de Figueiredo, Parana Basin, Brazil; early Lochkovian ... [more ▼]

An exceptionally large specimen of the early land plant Cooksonia paranensis Gerrienne et al. has been discovered from the type locality (Jackson de Figueiredo, Parana Basin, Brazil; early Lochkovian, Early Devonian). This nearly complete specimen consists of five dichotomous axes attached at their base to a small thalloid(?) structure. Each terminal axis segment ends in an expanded, cup-like, empty tip. Three interpretations of the specimen are proposed. (1) The whole specimen is a gametophyte of the Sciadopkyton-type, with a central area from which five axes depart; under this interpretation, the terminal cups are gametangiophores. (2) The basal structure represents the remains of a rhizome bearing five upright aerial axes, in which case the whole plant is a sporophyte. (3; our favoured hypothesis) The specimen is a cluster of five individual sporophytes still attached to the remains of a small female or bisexual gametophyte. In the latter case, this fossil is evidence that reduced thalloid gametophytes and branched axial sporophytes are plesiomorphic among the earliest eutracheophytes. We suggest that a major difference in life cycle defines a basal dichotomy in tracheophytes. Eutracheophyta, including all living vascular plants, have a heteromorphic, sporophyte dominant alternation of generations, whereas their extinct sister-group Rhymopsida (renamed here Paratracheophyta) is characterised by a more or less isomorphic alternations of generations. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

The permineralized lignophyte remains from Ronquières (middle Devonian, Belgium): preliminary results.

Conference (2006)

The Middle-Devonian proto-ovule Runcaria heinzelinii Stockmans 1968

Conference (2005)

Runcaria, a middle Devonian seed plant precursor

in Science (2004), 306(5697), 856-858

The emergence of the seed habit in the Middle Pateozoic was a decisive evolutionary breakthrough. Today, seed plants are the most successful plant lineage, with more than 250,000 living species. We have ... [more ▼]

The emergence of the seed habit in the Middle Pateozoic was a decisive evolutionary breakthrough. Today, seed plants are the most successful plant lineage, with more than 250,000 living species. We have identified a middle Givetian (385 million years ago) seed precursor from Belgium predating the earliest seeds by about 20 million years. Runcaria is a small, radially symmetrical, integumented megasporangium surrounded by a cupule. The megasporangium bears an unopened distal extension protruding above the multilobed integument. This extension is assumed to be involved in anemophilous pollination. Runcaria sheds new light on the sequence of character acquisition leading to the seed. [less ▲]

Evolution végétale: points de vue récents sur deux périodes-clés de l'histoire des plantes.

Conference (2004)