Section through Rhynie chert, a siliceous rock found in Scotland, showing the stems of a fossil plant Rhynia major. Rhynia was a primitive vascular plant consisting of an underground rhizome which bore upright aerial stems. The stems contained tracheids (primitive xylem cells for water transportation) & epidermal cells with stomata. There were no leaves or scales although the stems did have spiny hairs scattered over the surface. The fertile branches bore cylindrical sporangia at their tips, which contained the spores. These fossil plants grew to 30-60 centimetres (1-2ft) & are found mainly among rocks of the Devonian period.