• Webster's Revised Unabridged Dictionary
    • n Stigmaria (Paleon) The fossil root stem of a coal plant of the genus Sigillaria.
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Century Dictionary and Cyclopedia
    • n stigmaria A former genus of fossil plants, very abundant in many regions in the coal-measures, and especially in the under-clay, or clayey material (often mixed with more or less sand) by which most seams of coal are underlain; also [lowercase], a plant of this genus. These plants are cylindrical root-like bodies, nsually starting from a center in four main branches, and afterward bifurcating irregularly, and extending sometimes to great distances. The bodies are covered with small round depressions or scars arranged in lozenge-shaped patterns, and each the point of attachment of a ribbon-shaped filament or rootlet. In some cases the stigmarias have been found attached to trunks of Sigillaria, in such a position as would naturally be occupied by the roots with reference to the stem of the plant or tree; hence they have been admitted by most paleobotanists to be in fact the roots of the widely distributed coal-plant called Sigillaria. Some who maintain this, however, admit that the relation of the stigmarias to the plant itself was peculiar; while others believe that they were floating stems, able under favorable conditions to play the part of roots. This opinion has for its support the fact that thick beds of under-clay are frequently found almost entirely made up of remains of stigmarias, while not even a fragment of Sigillaria can be found in the vicinity.
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Chambers's Twentieth Century Dictionary
    • n Stigmaria the root of the fossil plant sigillaria, found in the coal-measures
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Webster's Revised Unabridged Dictionary
NL. See Stigma
Chambers's Twentieth Century Dictionary
L.,—Gr.,—stizein, to mark.


In literature:

These roots were Stigmaria, and the stuff into which they penetrated was an underclay.
"Scientific American Supplement, No. 447, July 26, 1884" by Various
Those roots penetrated into the under clay of the coal; and those roots were Stigmarias.
"Town Geology" by Charles Kingsley
In this richly ornamented Stigmaria the characteristic areolae present the ordinary aspect.
"The Testimony of the Rocks" by Hugh Miller
Binney, Mr., on stigmaria and sigillaria, 315.
"A Manual of Elementary Geology" by Charles Lyell
Their roots were formerly described as quite a distinct vegetable form (under the name of Stigmaria).
"The History of Creation, Vol. II (of 2)" by Ernst Haeckel