Sigillaria
Encyclopedia
Sigillaria is a genus of extinct, spore-bearing, arborescent (tree-like) plants which flourished in the Late Carboniferous
period but dwindled to extinction in the early Permian
period. It was a lycopodiophyte
, and is related to the lycopsids, or club-mosses, but even more closely to quillwort
s, as was its associate Lepidodendron
. Sigillaria was a tree-like plant, with a tall, 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 old leaf bases expanded as the trunk grew in width, and left a diamond-shaped pattern, which is evident in fossils. 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, microphyll
ous leaves, so that the plant looked somewhat like a tall, forked bottlebrush
. The plant bore its spores (not seeds) in cone-like structures attached to the stem. Sigillaria, like many ancient lycopods, had a relatively short life cycle - growing rapidly and reaching maturity in a few years.
Some have suggested that Sigillaria was monocarpic
, meaning that it died after reproduction, though this is not proven. It was associated with Lepidodendron
, the scale tree, in the Carboniferous
coal
swamps.
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
period but dwindled to extinction in the early Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
period. It was a lycopodiophyte
Lycopodiophyta
The Division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae. It is the oldest extant vascular plant division at around 410 million years old, and includes some of the most "primitive" extant species...
, and is related to the lycopsids, or club-mosses, but even more closely to quillwort
Quillwort
Isoëtes, also written Isoetes and commonly known as the quillworts, is a genus of plants in the class Isoetopsida and order Isoetales. They are considered "fern allies". There are about 140-150 species, with a cosmopolitan distribution but often scarce to rare...
s, as was its associate Lepidodendron
Lepidodendron
Lepidodendron is an extinct genus of primitive, vascular, arborescent plant related to the Lycopsids . It was part of the coal forest flora. They sometimes reached heights of over , and the trunks were often over in diameter, and thrived during the Carboniferous period...
. Sigillaria was a tree-like plant, with a tall, 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 old leaf bases expanded as the trunk grew in width, and left a diamond-shaped pattern, which is evident in fossils. 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, microphyll
Microphyll
The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based...
ous leaves, so that the plant looked somewhat like a tall, forked bottlebrush
Bottlebrush
Callistemon is a genus of 34 species of shrubs in the family Myrtaceae, all of which are endemic to Australia. It is sometimes considered a synonym of Melaleuca, and four Callistemon species from New Caledonia were moved to that genus by Lyndley Craven and John Dawson in 1998...
. The plant bore its spores (not seeds) in cone-like structures attached to the stem. Sigillaria, like many ancient lycopods, had a relatively short life cycle - growing rapidly and reaching maturity in a few years.
Some have suggested that Sigillaria was monocarpic
Monocarpic
Monocarpic plants are those that flower, set seeds and then die. Other terms with the same meaning are hapaxanth and semelparous. The term was first used by Alphonse de Candolle....
, meaning that it died after reproduction, though this is not proven. It was associated with Lepidodendron
Lepidodendron
Lepidodendron is an extinct genus of primitive, vascular, arborescent plant related to the Lycopsids . It was part of the coal forest flora. They sometimes reached heights of over , and the trunks were often over in diameter, and thrived during the Carboniferous period...
, the scale tree, in the Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
swamps.