Embryophytic sporophytes in the Rhynie and Windyfield cherts

Abstract

Brief descriptions and comments on relationships are given for the seven embryophytic sporophytes in the cherts at Rhynie, Aberdeenshire, Scotland. They are Rhynia gwynnevaughanii Kidston & Lang, Aglaophyton major D. S. Edwards, Horneophyton lignieri Barghoorn & Darrah, Asteroxylon mackiei Kidston & Lang, Nothia aphylla Lyon ex Høeg, Trichopherophyton teuchansii Lyon & Edwards and Ventarura lyonii Powell, Edwards & Trewin. The superb preservation of the silica permineralisations produced in the hot spring environment provides remarkable insights into the anatomy of early land plants which are not available from compression fossils and other modes of permineralisation. They include soft tissues, such as those surrounding stomata, rhizoids, apical and lateral meristems, and diversity in conducting cells, with inferences for palaeoecophysiology, including water use efficiency, transport and absorption, and for growth processes and patterns.

Belowground rhizomes in paleosols: The hidden half of an Early Devonian vascular plant

“…The existence of clonal growth similar to that of Drepanophycus is known to have occurred among Pragian zosterophyllopsids, and has been demonstrated clearly for Bathurstia (17,18). Rhizomatous habit also occurred in the Early Devonian rhyniopsids (21,22), early euphyllophytes, and other groups (14). Most Rhynie Chert plants of Early Devonian age have rhizoid-based rhizomatous axes, which are either surficial or shallowly subterranean at a millimeter-scale depth (22,23).…”

“…Rhizomatous habit also occurred in the Early Devonian rhyniopsids (21,22), early euphyllophytes, and other groups (14). Most Rhynie Chert plants of Early Devonian age have rhizoid-based rhizomatous axes, which are either surficial or shallowly subterranean at a millimeter-scale depth (22,23). Large woody rhizomes of aneurophytalean progymnosperms have been found in the Middle Devonian of New York, alongside cladoxylopsid and lycopsid trees (7).…”

“…Although the small aboveground size could suggest that the belowground components of these plants were similarly small and therefore limited in their impact on sediments, fossils of their belowground structures such as roots or rhizomes are rare and incomplete (16)(17)(18)(19)(20)(21)(22)(23). Some species have been recorded as bearing shallow rooting systems (or root-like structures) (16)(17)(18)(19)(20), others as having surficial or shallowly subterranean rhizomatous axes with rhizoids (21)(22)(23). Thus, the geochemical effect of these plants on the substrate (or soils) was presumably limited (11), and their capacity for landscape stabilization was trivial.…”

The Origin and Early Evolution of Roots

“…The development of rhizoids on rhizomatous axes exhibited variation and flexibility. They were quite short and present on all surfaces in some species (Lyon and Edwards, 1991), whereas they were longer and confined to ridges of tissues or perhaps further localized in patches in others (Kerp et al, 2001;Edwards, 2004;Fig. 1F).…”

A Whole Plant Herbaceous Angiosperm from the Middle Jurassic of China

“…On one hand, primary gro wth may produce organs bigger than those of Juraherba. For example, the early land plant Rhynia may produce an axis up to 3 mm in diameter (Edwards, 2003), in contrast to only 1.16 mm wide lower portion of Ju raherba. This contrast suggests that the size of Juraherba is with in the scope of primary growth.…”