Paläobotanik

Hirmer, Max

doi:10.1007/978-3-642-92425-5_5

Cited by 5 publications

(2 citation statements)

References 32 publications

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“…Com pression specimens of these cones exhibit an ex tended range of features, including sporangiophores that arise immediately above, midway, or just below bract whorls. Sporangial number includes taxa con taining one (M etac alamo st achy s [HIRMER 1927]); two (C alamo st achy s bisporangiata [ABBOTT 1968], C. noei [DARRAH 1969]); or four (i.e., species of Palaeostachya) sporangia per sporangiophore. Struc turally preserved calamitean cones illustrate an equally diverse range of sporangiophore positions; however, the number of sporangia per sporangio phore is either two or four.…”

Section: Introductionmentioning

confidence: 99%

Studies of Paleozoic Calamitean Cones: Weissia Kentuckiense Gen. et Sp. Nov.

Rothwell¹,

Taylor²

1971

Botanical Gazette

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The recent discovery of a new petrified fructification from the Lewis Creek coal ball locality in eastern Kentucky adds to our knowledge of the structure and diversity of c alamitean cones. The incomplete specimen measures 4.8 cm long and 6.0 mm in diameter, and is composed of alternating bract and sporangiophore whorls. Approximately 24 bracts are present in each whorl. Bracts arise at right angles to the axis and are fused into a shallow disk for 2.0 mm before arching distally and becoming free. Six sporangiophores arise obliquely from slightly above each bract disk; each sporangiophore bears two large pendant sporangia that are attached along their distal and tangential surfaces. Sporangia! walls are a single cell layer thick and are characterized by internal cell lumen partitions. The distal ends of the sporangiophores are fused to form a continuous ring of tissue that surrounds the sporangia. Features of the new cone are discussed in relation to those of other calamitean cones of s imilar age.

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Section: Introductionmentioning

confidence: 99%

Studies of Paleozoic Calamitean Cones: Weissia Kentuckiense Gen. et Sp. Nov.

Rothwell¹,

Taylor²

1971

Botanical Gazette

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“…It is possible that M. yixingensis partly includes S. wusihense. Other species, such as S. mirabile (Nathorst) Hirmer (Hirmer 1927), are similar to M. yixingensis in branching and the helical arrangement of the leaf bases. However, S. mirabile differs from M. yixingensis by its fusiform leaf base, with well-developed wrinkles between the leaf cushions, and lacks spiny appendages along the edges of leaf cushions.…”

Section: O M P a R I S O Nmentioning

confidence: 99%

A novel lycopsid from the Upper Devonian of Jiangsu, China

Wang¹,

Berry²

2003

Palaeontology

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ABSTRACT. A new lycopsid, Monilistrobus yixingensis gen. et sp. nov., is described from the Wutung Formation (Famennian, Upper Devonian) of Jiangsu, China. The plant has many features typical of other Upper Devonian lycopsids, including dichotomous branching, helically arranged obovate expanded leaf bases, linear leaves with spiny appendages along the lateral margins, sporophylls widened proximally, and one elliptical sporangium attached to the adaxial surface. The most distinctive novel feature of the plant is that the modi®ed sporophylls are arranged tightly into fertile zones or cone-like structures that are separated by lengths of axes with more lax sterile microphylls only: therefore the cone-like structures are strung along the branches like beads on a necklace.

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Aspects of Cone and Ovule Ontogeny in Cryptomeria (Taxodiaceae)

Takaso

Tomlinson

1989

American J of Botany

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The axillary complex of female cones of Cryptomeria is initiated as a tangentially extended triangular structure with a rounded apex. It is bilaterally symmetrical. Structures interpreted as prophylls are differentiated first, but they become insignificant in later development. They are succeeded by two successive pairs of lobes, each lobe being the common primordium for an adaxial ovule and a tooth. The ovule initially much exceeds the tooth. The apex of the complex has a diversity of fates and may differentiate as an ovule‐tooth pair. A one‐to‐one relation between teeth and ovules may be lost by abortion of ovules. The initial relation between teeth and ovules is obscured in later development due to extension of tissues at the base of the complex associated with considerable enlargement of the teeth. Histogenesis of the various parts is described, together with the vascular system. There is a vascular supply to the tooth but not the ovule. The results support a direct comparison with the extinct transition conifers Pseudovoltzia and Aethophyllum but do not fully support Florin's generalized model for the arrangement of parts in the axillary complex of conifers.

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Paläobotanik

Cited by 5 publications

References 32 publications

Studies of Paleozoic Calamitean Cones: Weissia Kentuckiense Gen. et Sp. Nov.

Studies of Paleozoic Calamitean Cones: Weissia Kentuckiense Gen. et Sp. Nov.

A novel lycopsid from the Upper Devonian of Jiangsu, China

Aspects of Cone and Ovule Ontogeny in Cryptomeria (Taxodiaceae)

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