A brief introduction
The nematophytes, which means
"filamentous plants", are known for about 150 years as fossils from
the Silurian and Lower Devonian but they are still so poorly understood
that lately they are not even listed among plant fossils but more
cautiously under "Enigmatic Organisms"  (**). Their sizes and shapes
range from millimeter-size spheres (Pachytheca,
see picture) and centimeter-size flaps
and others, see picture below) to meter-size trunks
Essentially they are made up of two or more
types of filaments which nearly always appear as empty tubes. The tubes
typically form a chaotic tangle (*) with a more or less distinct
for some plane or direction. In some species, part of the filaments are
aligned perpendicular to the surface, most perfectly so in the case of Pachytheca.
Nematophytes are very rare fossils in the
Lower Devonian Rhynie
chert but the few specimens found lately provide answers
to some of the questions lingering in the literature for a long time.
However, they pose new questions, too, as it is apparent from the picture below right.
The nematophytes from the Rhynie chert represent at least 7
species, among them non-described ones. The
tubes of the live nematophytes seem to have been embedded in gel.
The long-standing enigma of an unexpected
cellular pattern known as Nematothallus
cuticle, often found together with coalified
tangles of filaments, is demystified
here for the first time.
The much bigger enigma of Prototaxites
has aroused the imagination of scientists as well as fossil collectors,
giving rise to wild speculations ever since it was discovered up to now
(2010). The latest attempt to demystify the great Prototaxites by
assorting it with humble liverworts is thwarted here with the help of
small nematophytes from the Rhynie chert.
Most of the discoveries and conclusions discussed in the contributions
up to Nr. 41 had been presented at EPPC 2010 .
Lately, Nematoplexus has turned out more enigmatic than previously thought, with details never seen before, as the big "knot" in this image on the right.
* On the Aberdeen Univerity website , the
characteristic feature of Nematoplexus,
spirally wound tubes, is ascribed to virtually all nematophytes.
Apparently they did not know Pachytheca with straight tubes
and other nematophytes with irregularly wavy
tubes, as in the image above.
Also in , chapter on bryophytes, it is proclaimed that "One
interesting hypothesis suggests that several of the enigmatic ...
nematophytes may represent remains of ancient liverworts ... . ... At
least some of the tubular aggregations assigned to nematophytes have
been reinterpreted as ... liverwort rhizoids, ... ." That hypothesis is
refuted in Rhynie
For new developments see  and the discussion in Rhynie
Chert News 1
specimen in chert, central
weft of big tubes, new species ?
big variety, new species ?
flat nematophyte, Nematophyton taiti
first specimen in chert, off-centre
liverwort connection of nematophytes and
with a wry twist ?
Rhynie Chert News 40
liverwort connection of Cosmochlaina
nematophyte propagule ?
(?) – details
Chert News 51
Chert News 71
Nematoplexus - more
details, more questions (1)
Chert News 86
tangle of very thin tubes, 6-8Ám
Chert News 92
glades in the weft of big tubes
Chert News 98
weft of big tubes in a gel lump with dried-up surface layer
Chert News 99 weft of narrow tubes with peculiar details
Chert News 102 Nematoplexus - more
details, more questions (2)
Chert News 106 Nematoplexus big and small, new charophyte gametangia, Castracollis
Chert News 107 first 3D-Nematothallus
Chert News 122 Nematoplexus
- enigmatic ever
Chert News 123 Nematoplexus
spiral, 3 turns
Chert News 126 enigmatic knots of Nematoplexus
H.-J. Weiss updated 2016, 2017, 2018
 T.N. Taylor,
E.L.Taylor, M. Krings: Paleobotany, Elsevier 2009.
 P. K. Strother:
Clarification of the genus Nematothallus,
J. Paleont. 67 (1993),
 H. Steur:
Weiss: Enigmatic Organisms - Insights
derived from new finds, Poster presentation, EPPC Budapest
 M.R. Smith, N.J.
A new view on Nematothallus:
Coralline Red Algae from the Silurian of Gotland.
Palaeontology 56(2013), 345–357.