Ventarura cross-section with dark ring insideVentarura
deutsche Version

The fossil plant seen here on a cross-section of a small sample found in 1998 had remained enigmatic until a first publication on Ventarura appeared in 2000 [1]. Incidentally, this sample with the first own find of Ventarura contains also an incurved tip like that of most ferns, which has remained the only one ever seen: Rhynie Chert News 3
Among the Higher Plants in the Rhynie chert, Ventarura had been discovered last. It was thought to be restricted to a separate and narrowly localized variety of the Rhynie chert, named Windyfield chert. (Hence the name Ventarura, which means "windy field".)  This assumption has turned out not true. All own finds of Ventarura are from other sites.  
Like the previously discovered Trichopherophyton, Ventarura belongs to the zosterophylls, a group of plants widely distributed in the Lower Devonian.
The distinctive feature, a concentric tube with well seen cellular structure while all other tissue had virtually vanished, is found only in the upper parts of the plant which seem to be less often preserved. This persistent tube, seen
on cross-sections as a nearly circular ring contrasting to the mostly shrivelled outside, is often conspicuous for its apparently strong cell walls with dark stain. Its original interpretation as sclerenchyma [1,2] is rejected here: Rhynie Chert News 60 , 82, 174
Ventarura parts without a ring on cross-sections are usually not recognized as such. Even Ventarura sections with ring may escape notice if the outline is not rugged but smoothly circular and the cell walls are not stained dark but pale: Rhynie Chert News 58.
One or more younger shoots inside an older one most probably indicate a zosterophyll. (See
Rhynie Chert News 16.)
Hollow straws of Aglaophyton with layers of well-preserved cells below the surface may easily be (and really had been) mistaken for Ventarura: Rhynie Chert News 66.
In order to tell Ventarura from Aglaophyton cross-sections, the following rules can be helpful:
It is Ventarura if the ring of well-seen cells is ...
 ... (nearly) circular but the outline of the section is rugged,
 ... well away from the outline,

It is virtually never
Ventarura if the epidermis is still there: Rhynie Chert News 61, 91.

It is not known whether the decay-resistant tube amidst the cortex makes Ventarura unique or is present in some other fossil or extant plant, too. The hollow straw aspect occasionally seen with Aglaophyton, well known but misinterpreted, is possibly brought about by essentially the same sequence of processes and hence can lead to an explanation of the conspicuous phenomenon in either plant:
Rhynie Chert News 83.
Judging from more than a dozen small chert samples with Ventarura found hitherto, this plant seems to be more widely distributed in the chert but had been overlooked. Hence, more finds are likely, which may help to answer the remaining questions raised by the peculiar features of this fossil.
 A cross-section with unique aspect is shown in Rhynie Chert News 96.
Considering that Ventarura and Trichopherophyton are the least abundant ones among the land plants in the Rhynie chert, the presence of the two zosterophylls in one chert sample must be a rare coincidence: Rhynie Chert News 95.
As a surprise, a raw sample surface shows a picturesque section of
Ventarura with the xylem seen most clearly: Rhynie Chert News 171 .
Sample: Rh3/5 (0.2kg) Part5, found in 1998.

H.-J. Weiss       2012,     emended 2014, 2016, 2021.

C.L. Powell, D. Edwards, N.H. Trewin:  A new vascular plant from the Lower Devonian Windyfield chert, Rhynie,
      Trans. Roy. Soc. Edingurgh, Earth Sci. 90 (2000 for 1999), 331-349.
[2]  H. Kerp, H. Hass: Ökologie und Reproduktion der frühen Landpflanzen. Ber. d. Reinh.-Tüxen-Ges. 21, 111-127. Hannover 2009.

Site map
Rhynie Chert News
Rhynie chert