|This page is for informational purposes only and none of the figure specimens are available for sale.
Links to our pages containing Rhynie Chert thin sections that can be purchased are shown below.
The Rhynie Chert of Scotland is a Lower Devonian deposit that preserves one of the earliest terrestrial faunas. It is a unique
deposit in that it preserves a fauna and flora that once thrived ina volcanic hot springs environment. It is believed that the
palaeoenvironment was like that seen in Yellowstone National Park with silica and mineral rich geysers. It was in and around
the ponds created by such geysers that the Rhynie Chert fauna and flora lived.
Periodically, waters from the hot springs inundated the land, swamping the plants. Some were knocked flat while others
remained standing upright even though they were now completely covered by water. The silica rich waters rapidly
penetrated the plants, and as mineral replacement took place they were preserved in place (still upright in growth positions)
in exceptional detail. (The mineral deposits and crusts seen around modern day geysers give an indication of how obvious
deposition of minerals can be). The silica minerals eventually formed chert, and with little time for the plants to decay or
become compressed fully 3 dimensional plants are preserved that show every detail, right down to fungi that lived within the
cells of plants.
The deposit is so important because it preserves fossils at the cellular level. The cells of plants are the most notable as the
xylem, cortex, phloem and cuticle cells can all be preserved. Rooting systems (rhizoids), sporangia (spore pouches) and
even the spores themselves from the plants are known. In addition several species if fungi and lichens are known, even the
insects that crawled and hopped between the plants have been 3 dimensionally preserved in the chert.
The fauna of the site does not initially appear extensive as only seven major forms of plants known, but when you consider
this is a very early terrestrial site that is not an unreasonable number. However, once you take into account the species
found that usually are not preserved in the fossil record the list rapidly grows - there are about half a dozen spores known,
the same number of lichens and fungi, then some cyanobacteria, and then there are the arthropods. With 20+ species
currently known it is easy to see why the site has been designated a Site of Special Scientific Interest by the Scottish
government. This means that although surface collecting is permitted you cannot dig at the site. The chert itself does not
outcrop naturally at the surface, instead it is glacial float blocks that have to be collected.
The University of Aberdeen has an exceptional site dedicated to the Rhynie Chert and anyone wanting many more details
can spend hours reading the information they present. Below is our quick reference guide to Rhynie Chert fossils. It is based
solely on specimens that we have had in the past so it is not a complete list. It does, however, give a good overview of the
specimens we can generally offer for sale.
Aglaophyton was a low, creeping plant with smooth, leafless aerial
axes that grew to ~15cm long. The axes dichotomously branched and
bore at their ends pairs of bud-shaped sporangia. A network of
rhizomes grew across the surface of the ground providing stability
and a means of feeding. Aglaophyton is the most common and best
known of the Rhynie plants.
The aerial axes of Aglaophyton were up to 7mm in diameter. When
viewed in cross section the aerial axes can be divided into a number
of different zones. The central zone is the vascular strand, which
consists of a xylem surrounded by a phloem. Cells of the xylem are
sub-rhomboidal in shape with dark colored cell walls and gradually
increase in size from the center. Beyond the phloem is an inner cortex
that consists of loosely packed cells with abundant intercellular air
spaces. The outer cortex is made up of elongate cells that are
uniformly sized and tightly packed. Often a dark boundary layer exists
between inner and outer cortex. This dark zone is invariably made up
of fungal hypha that lived within the cortex of the plant.
The rhizomes of Aglaophyton have a similar morphology to the aerial
axis but can bear rhizoids on the ventral sides.
The sporangia are ovoid, the proximal end bearing a short stem that
was attached to the aerial axis. The sporangia is thick walled and
divided into two distinct sections. The outer section is comprised of a
dark elongate cell-like structure. The thicker inner section is an
undifferentiated mass with a somewhat fibrous appearance. It is not
uncommon to find spores within the sporangia or among stems of this
species. Aglaophyton spores have been assigned to the genus
|All drawings are the author's interpretations of reconstructions published
by the University of Aberdeen
|Aglaophyton major aerial axes left and centre,
|Aglaophyton major rhizome bearing a rhizoidal tuft on
the right side. Most likely in life this would have been
located on the underside of the rhizome
|Top: Aglaophyton major sporangia bearing Retusotriletes
spores. Above: Enlargement of the two distinct layers of
the sporangia. Note the black elongate cells of the outer
layer and white mass of the inner layer.
|An additonal example of a near complete Aglaophyton major sporangia with spores.
The elongate cells of the outer layer are again evident in the image (right).
|Left: An example of an Aglaophyton major aerial axis that has begun to decay (evidenced by the voids).
Right: Another axis in a more advanced state of decay.
Nothia was an unusual plant in that the aerial axes had an irregular,
undulating surface texture, unlike any other Rhynie species. The aerial
axes branched off the rhizomes and grew to a height of 15 to 20 cm.
Kidney shaped sporangia were present on the tips of the fertile axes.
As in most other species from the chert, Nothia showed repeated
dichotomous branching. In cross section the epidermal cell structure
seen in Nothia is unique in the Rhynie chert. An alternating
arrangement of large elongate cells and shorter, small cells is seen
throughout the epidermis and is constant throughout the aerial axes.
The cortex is rarely preserved with any clarity, but it appears to be
only weakly differentiated with elongate cells in the outer cortex, and
shorter, smaller cells in the inner cortex. It is not unusual for the
cortex of this plant to show a double ovoid xylem strand. These dark
celled structures are clearly preserved in many cases and are
believed to represent the dichotomy of the aerial axes.
The rhizomes of Nothia are also distinct in that they show a
pronounced ventral ridge bearing rhizoids. The xylem and cortex cell
structure are similar in shape to that seen in the aerial axis and the
epidermis of the rhizomes bears the same alternating succession of
large and small cells.
The sporangia are usually found as looped structures which have
clearly opened to release the spores. No spores have been found
within the sporangia. The maximum size of the sporangia was ~3 mm
long. Nothia was uncommon in the Rhynie Chert flora, although
specimens are found in association with other plants, especially
|Left: The axes of Nothia showing very little differentiation and no cell structure to the cortex.
Right: the double xylem typical of Nothia. Again the specimen shows little differentiation of the cortex.
|Devonian Plants of the
Horneophyton was an unusual plant in that the aerial axes were long, but
thin, and were supported by a large, bulbous subterranean rhizome. The
aerial axes reached diameters of only 2 mm but could be almost 20 cm
long. The rhizome was a single mass that was either circular or lobed
and could be 2 to 3 cm in diameter. Rhizoidal tufts were abundant on the
surface of the rhizome. Horneophyton could be classed as a vascular
plant as the water carrying cells show distinct thickening. However, the
presence of a collumella (central strand) within the sporangia is more
indicative of mosses and liverworts. The exact systematic position is
therefore uncertain, although it is seems the plant preferred wet, sandy
In cross section, the axes of Horneophyton show little differentiation and
a pronounced cell structure is not evident. A narrow central xylem is
present and consists of small, dark walled cells.
The sporangia of Horneophyton appear at the tips of the aerial axes.
They are cup-shaped with a distinct central columella. Spore release
was from the ‘mouth’ end of the cup which would split open to release
the spores. The spores are not uncommon in the Rhynie Chert although
they measure only 40 to 50 microns wide. Horneophyton spores have
been assigned to the species Emphanisporites decoratus. Each spore
has the appearance of 3 loosely joined triangular structures with short,
spinose projections and radial ornamentation. It is believed that
Horneophyton was one of the earliest colonizers of the chert
environment as it is often found in monotypic stands, suggesting it grew
in areas before other plants were able to take hold. The large rhizome
would have allowed abundant uptake of nutrients and also provide a
|Left: The multilobed root ball of Horneophyton. Right: An enlargement of one of the large rhizoidal tufts.
Palaeomyces fungal cysts
|Left: Sketch of Horneophyton sporangia. Right: An enlargement of a cup shaped sporangia with spores.
Fungi are abundant in the Rhynie Chert, their cysts and hypa
being found in association with many other species. Fungal
cysts are common throughout the Rhynie chert, but the most
frequnetly encountered species are simple, unornamented
cysts appearing as circles or spheres within the chert (often
within the cortex of Aglaophyton and other plants). The two
dominant species are:
1.) Palaeomyces gordoni - a larger, thick walled species that
measures ~100 microns (0.1mm) wide.
2.) Palaeomyces asteroxyli - a small thin walled species
measuring only ~30 microns (0.03 mm) wide.
It is not uncommon for the larger species to be contain within
their cavities abundant specimens of the smaller forms.
Fungal hypha are also very common within the chert. Hypha
are a network of simple organic strands with budding vesiculae
(reproductive, cyst-like structures). Several species occur in
the Rhynie chert but all are microscopic, measuring <0.1mm
long. Most species are encountered within the cortex of the
higher plants where the fungi lived in symbiosis with the host.
Glomites rhyniensis is the most abundant fungal hypha and
the axes of Aglaophyton are particularly noteworthy hosts -
the dark ring within the cortex of almost every Aglaophyton
axis is formed by the presence of fungal hypha.
|Above: An axis of Aglaophyton containing both species of
Palaeomyces and the dark ring of Glomites rhyniensis
|Above: An axis of Aglaophyton containing the large cysts of
|Left: Palaeomyces asteroxyli
Right: Palaeomyces gordoni
|Above left: An axis of Aglaophyton containing the dark ring formed by Glomites rhyniensis.
Right: enlargement of the Glomites hypha.
Arthropod remains are not common in the chert, but a wide variety of forms are present including mites, harvestman spiders
and trigonotarbid spiders, centipedes. The most frequently encountered evidence of arthropod activity is coprolites, which
are made up of the spores of plants.
|Above left: A pair of arthropod coprolites made up of digested spores. Right an enlargement of an arthropod coprolite.
|Above: The segmented antennae of Crussolum sp. a centipede
|Left: Another sign of arthropod activity - this axis of Aglaophtyoton has been punctured (an inhabited?) by a parasite.
Right: A segmented portion of thorax from the silver fish like arthropod Lepidocaris rhyniensis