Sigillaria is a genus of extinct, spore-bearing, Lepidodendrales, known from the Carboniferous and Permian periods. It is related to the more famous Lepidodendron, and more distantly to modern Isoetes.
Fossil records
This genus is known in the
from as early as the
Middle Devonian or the Late
Carboniferous period
[ Hans' Paleobotany Pages - The clubmoss tree Sigillaria] but dwindled to extinction in the
Cisuralian period (age range: from 383.7 to 254.0 million years ago).
[ Encyclopædia Britannica] Fossils are found in Great Britain, United States, Canada, China, Korea, Tanzania and Zimbabwe.
Description
Sigillaria was a tree-like plant reaching a height up to ,
and lycopsids were capable to reach a height of up to .
[ ] These lycopsids had a tall, single or occasionally forked trunk
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
were attached directly to the stem and grew
in a spiral along the trunk.
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.
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, leaves,[Sebastián González, D. and Celia Gutiérrez, M. (2014). El Bosque Petrificado de Olta: 300 millones de años después ]
The underground structures of Lepidodendrales including Sigillaria and Lepidodendron are assigned under the form taxon, Stigmaria. The lycopsids had rhizomes or shoot-like rhizomorphic axes, with lateral appendages attached from the circular scars, forming an underground network of branched rootlets. These stigmarian rootlets branched dichotomously from the rhizomorphs similar to Isoetes, and spread throughout the coal swamp forest areas where the lycopods were commonly found. Root hairs from the rootlet scars identified in Stigmaria fossils were attached when the lycopsids were alive.
Sigillaria, like many ancient lycopods, had a relatively short life cycle - growing rapidly and reaching maturity in a few years. Sigillaria may have been monocarpic, meaning that it died after reproduction, though this is not proven.
Species
Species within this genus include:
[ Hans' Paleobotany Pages - Species of Sigillaria]
-
S.alveolaris Brongniart (1828)
-
S.barbata Weiss (1887)
-
S.bicostata Weiss (1887)
-
S.boblayi Brongniart (1828)
-
S.brardii Brongniart (1828)
-
S.cancriformis Weiss (1887)
-
S.cristata Sauveur (1848)
-
S.cumulata Weiss (1887)
-
S.davreuxii Brongniart (1828)
-
S.densifolia Brongniart (1836)
-
S.elegans Sternberg (1825)
-
S.elongata Brongniart (1824)
-
S.fossorum Weiss (1887)
-
S.hexagona Brongniart (1828)
-
S.loricata Weiss (1887)
-
S.mammiliaris Brongniart (1824)
-
S.menardi Brongniart (1828)
-
S.micaudi (Zeller (1886-1888)
-
S.monostigma Lesquereux (1866)
-
S.orbicularis Brongniart (1828)
-
S.ovata Sauveur (1848)
-
S.pachyderma Brongniart (1828)
-
S.principes Weiss (1881)
-
S.reticulata Lesquereux (1860)
-
S.rugosa Brongniart (1828)
-
S.saulii Brongniart (1836)
-
S.schotheimiana Brongniart (1836)
-
S.scutellata Brongniart (1822)
-
S.sillimanni Brongniart (1828)
-
S.tesselata Brongniart (1828)
-
S.transversalis Brongniart (1828)
-
S.trigona Sternberg (1826)
-
S.voltzii Brongniart (1828)
Gallery
File:Joggins-bark.jpg| Sigillaria lycopod fossil, Joggins, Nova Scotia, Canada
File:Stanhope Tree - geograph.org.uk - 2531669.jpg|Fossil of Sigillaria trunk attached to a Stigmaria (lycopsid rhizomes)
File:Sigillaria1.jpg| Sigillaria on display at State Museum of Pennsylvania, from Sharon, Mercer County, Pennsylvania
File:Sigillaria2.jpg| Sigillaria (bark) on display at State Museum of Pennsylvania, from Scranton, Lackawanna County, Pennsylvania
File:Sigillaria sp.4 - Carbonifero.JPG|Replica of Sigillaria sp. at the University of A Coruña
File:Lycopsid joggins mcr1.JPG| In situ Lycopsid that is probably Sigillaria from the Pennsylvanian Joggins Formation in Nova Scotia
File:Sigillaria notata.jpg|A close-up of the leaf scars on a Sigillaria notata
File:Sigillaria mammillaris - Naturmuseum Freiburg - DSC06753.jpg| Sigillaria mammillaris
File:Sigillaria elegans fossil.jpg| Sigillaria elegans
File:PSM V18 D632 Restoration of sigillaria.jpg| Sigillaria restorations
File:Dawson upright fossil.gif| Sigillaria preserved in the cliffs at Joggins, Nova Scotia, Canada
File:Lycopod bark.jpg|Lycopod bark (possibly an early species of Sigillaria) showing leaf scars, from the Middle Devonian of Wisconsin.
File:Sigillaria reconstrucción.jpg|Restoration
Bibliography
-
William A. DiMichele, Richard M. Bateman: The Rhizomorphic Lycopsids: A Case-Study in Paleobotanical Classification. Systematic Botany, 1996, volume 21, pages 535-552.
-
Thomas N. Taylor, Edith L. Taylor, Michael Krings: Paleobotany. The Biology and Evolution of Fossil Plants. Second Edition, Academic Press 2009, , pages 303-307
-
J. W. Sir Dawson - On the structure and affinities of Sigillaria, Calamites and Calamodendron - Paperback – August 16, 2011
-
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.
External links
