Another tangle of tubes in chert
The nematophytes, from palaeobotany monographs also known as Enigmatic
Organisms, are not often seen in the Rhynie chert. Judging from the few
samples hitherto found, they come in tangles of tubes which can be more
or less aligned, or even strictly aligned as with Pachytheca.
There are several species, among them apparently unnamed ones.
Some of them seem to consist of smooth-walled tubes only, as those
presented in Rhynie
Chert News 13,
consist of a combination of tubes with smooth walls and others with
spirals or annular rings on the walls .
Fig.1: Nematophyte tube fragment, 26Ám, spacing mostly 5-6Ám. Width of
the image 0.8mm.
behind the different types of tubes and their possible mutual relation
remain obscure. They are thought to somehow originate within "branch
knots" of Nematoplexus 
but the present sample does not provide evidence for this although a
branch knots surrounded by smooth-walled screw-like
tubes are seen only 3cm away. The tubes with patterned walls are found
scattered fragments only, similar as in Fig.1, with one quite
unexpected exception seen in Fig.2, where the large tubes seem to be
embedded in a separate lump of gel with a tangle of poorly visible tiny
As noticed by P.
, the fossil in Fig.2 strongly resembles Nematothallus pseudo-vasculosa
known from compressions . The size data are roughly compatible, including
the dimly seen tiny filaments in Fig.2 which seem to correspond with "tubes
between 1.5 and 3Ám in diameter" seen on the lectotype of that
Similar as with the tube fragments scattered sparsely
throughout the chert, the tubes in the gel lump do not show branching
nor other remarkable features, perhaps except for one peculiarity
poorly seen above left: A big tube suddenly reduces its diameter to
less than half.
What looks like a series of orderly turns of a screw, as in Fig.1 below
right, is often interrupted by disorder due to merging or branching
turns, as repeatedly seen in Fig.2.
assemblage of nematophyte tubes as a
separate patch, probably of gel , with various diameters centered
around an average of 20Ám, and a wide variety of spacings between
the image 1.9mm, same scale as above.
Drawing conclusions from
only one sample may not be justified here but formulating questions may
be appropriate. The tubes with patterned walls in this sample are
not seen near branch-knots of Nematoplexus.
Hence similar tubes seen elsewhere attached to branch-knots pose the
question what makes them do so. Even in cases where there is no
connection the question remains why patterned tubes are found near
smooth-walled screws of Nematoplexus,
and particularly, why this veritable 3D-version of Nematothallus pseudo-vasculosa,
too, seems to prefer a place where Nematoplexus
Finally it may be mentioned that this sample of mere 0.28kg
found in 2003 has offered several remarkable items: Nematoplexus
with tubes larger and smaller than hitherto known (2009), Castracollis
eye (? 2015) and unidentified moults, an unknown archetypal charophyte
(2016), and possibly the first 3D-version of Nematothallus pseudo-vasculosa,
H.-J. Weiss 2017
On the fragmentary remains of an organism referable to the
from the Rhynie chert, Nematoplexus
Trans. Roy. Soc. Edinburgh
65(1961-62), 79-87, 2
error on Plate I Fig.1: not x19 but x1.5)
private communication (2017).
Clarification of the genus Nematothallus
J. Paleont. 67(1993), 1090-1094.
 W.H. Lang:
On the plant-remains from the Downtonian ... .
Phil. Trans. Roy. Soc. London B 227(1937),