Sigillaria

Sigillaria Temporal range: Carboniferous to Permian
Sigillaria tree (Stigmaria) from Stanhope, County Durham, UK
Scientific classification
Kingdom:	Plantae
Division:	Lycopodiophyta
Class:	Isoetopsida
Order:	Lepidodendrales
Family:	Sigillariaceae
Genus:	Sigillaria

Sigillaria is a genus of extinct, spore-bearing, arborescent (tree-like) plants. It was a lycopodiophyte, and is related to the lycopsids, or club-mosses,^[1] but even more closely to quillworts, as was its associate Lepidodendron.

Fossil records

This genus is known in the fossil records from the Late Carboniferous period ^[2] but dwindled to extinction in the early Permian period (age range: from 383.7 to 254.0 million years ago).^[1] Fossils are found in United States, Canada, China, Korea, Tanzania and Zimbabwe.^[3]

Species

Fossil of Sigillaria trigona, on display at National Museum (Prague)

Species within this genus include:^[4]

Description

Sigillaria was a tree-like plant reaching a height up to 30 meters,^[2] with a tall, single or occasionally forked trunk^[1] that lacked wood. Support came from a layer of closely packed leaf bases just below the surface of the trunk, while the center was filled with pith. The long, thin grasslike leaves^[5] were attached directly to the stem and grew ^[2] in a spiral along the trunk.^[1] The old leaf bases expanded as the trunk grew in width, and left a diamond-shaped pattern, which is evident in fossils. These leaf scars were arranged in vertical rows.^[2] The trunk had photosynthetic tissue on the surface, meaning that it was probably green.

The trunk was topped with a plume of long, grass-like, microphyllous leaves,^[5] so that the plant looked somewhat like a tall, forked bottle brush. The plant bore its spores (not seeds) in cone-like structures ^[5] attached to the stem.^[1][6]

Sigillaria, like many ancient lycopods, had a relatively short life cycle - growing rapidly and reaching maturity in a few years. Some researchers have suggested that Sigillaria was monocarpic, meaning that it died after reproduction, though this is not proven.^[5] It was associated with Lepidodendron, the scale tree, in the Carboniferous coal swamps.^[2]

Gallery

• 
  Sigillaria on display at State Museum of Pennsylvania, from Sharon, Mercer County, Pennsylvania
• 
  Sigillaria (bark) on display at State Museum of Pennsylvania, from Scranton, Lackawanna County, Pennsylvania
• 
  Replica of Sigillaria sp. in a laboratory of practices of the Faculty of Sciences of the University of A Coruña
• 
  In situ Lycopsid that is probably Sigillaria from the Pennsylvanian Joggins Formation in Nova Scotia
• 
  Sigillaria Artist's Impression.

Bibliography

• William A. DiMichele, Richard M. Bateman: The Rhizomorphic Lycopsids: A Case-Study in Paleobotanical Classification. Systematic Botany, 1996, Band 21, S. 535-552.
• Thomas N. Taylor, Edith L. Taylor, Michael Krings: Paleobotany. The Biology and Evolution of Fossil Plants. Second Edition, Academic Press 2009, ISBN 978-0-12-373972-8. S. 303-307
• J. W. Sir Dawson - On the structure and affinities of Sigillaria, Calamites and Calamodendron - Paperback – August 16, 2011 ISBN 1175560871
• Silva Pineda, A. (2003). "Flora del Pérmico de la región de Izúcar de Matamoros, Puebla". En Soto, L. A. Agustín Ayala-Castañares: universitario, impulsor de la investigación científica. UNAM. p. 371. ISBN 9789703207893

References

External links

Wikimedia Commons has media related to Sigillaria.

• Fossil Plants Vol.II
• The Columbia Encyclopedia