Lepidodendrales

Scale Trees

The Lepidodendrales are an extinct lycophyte group that formed some of the first swamps on Earth. These trees grew to over 100 feet, and over 5 feet in diameter (similar in size to a large oak tree). These trees differed from modern trees, such that they were constructed with a small amount of wood, and large amounts of bark. This made the trees less stable than modern plants, and prone to falling over after a few years of maturity. This created large amounts of plant debris on the swamp floor, which piled up and was compressed over many, many years. This large amount of biomass became the coal that we use as fossil fuels today. The closest, living relatives are the quillworts, Isoetes.

Above: Reconstructions of several lepidodendrids

Ecology and Form

Stems 


Above: XS of stem showing large amounts of bark, but minimal wood

Below: outside bark pattern of Lepidodendron showing scale-like leaf scars

Above: Sigillaria bark (by Hectonichus - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=41691308)

Roots (Rhizomorph)

Above: Arboreous lycopsid tree stumps with stigmarian rhizomorphs exposed. A, Line drawing from Williamson (1887, xylograph 7). B, Specimen on public display at the Manchester Museum, United Kingdom. C, Whitefield Tree, displayed on the grounds of the University of Kentucky. D, Specimen illustrated in plate XIX in Potonié (1889). E, Specimen formerly displayed at the US National Museum of Natural History, USNM specimen 34989. A used with permission of the Palaeogeographical Society. B and C courtesy of Steve Greb. (DiMichele et al. 2022)

Leaves

Reproductive Structures

Lepidophylloides

Above: Lepidodendrid leaves (Lepidophylloides)

Below: Male lepidodendrid cone (Lepidostrobus)

Lepidostrobus

Diversity

Family Lepidodendraceae † (e.g. Lepidodendron, Lepidophloios, Hizemodendron)

Family Diaphorodendraceae (e.g. Diaphorodendron, Synchysidendron)

Family Sigillariaceae † (e.g. Sigillaria)

Family Ulodendraceae † (e.g. Paralycopodites)

Incertae sedis: Sublepidophloios, Bothrodendron, Bergeria, Asolanus

Taxa

Clevelandodendron ohioensis

Cystosporites

Diaphorodendron

Lepidocarpon

Lepidodendron

Lepidodendropsis

Lepidophylloides

Lepidostrobophyllum

Lepidostrobus

Lycospora

Otzinachsonia beerboweri

Classification

Embryophytes 

   └Polysporangiophytes

      └Tracheophytes

         └Eutracheophytes

            └Lycopsida

               └Lepidodendrales

Geologic Age

Clevelandodendron ohioensis

Above: Clevelandodendron ohioensis (from Figs 1-4, Chitaley & Pigg 1996)

Below: Otzinachsonia beerboweri. Photo by Walt Cressler.

Protolepidodendropsis pulchra

Protostigmaria eggertiana

Above: In-situ Protolepidodendropsis fossils (From Fig 4, Berry & Marshall 2015 

Sigillaria

Stigmaria

Oxroadia

Additional Resources