Rinistachya

Rinistachya is a genus of Late Devonian sphenopsid, currently containing one species, Rinistachya hilleri. It comprises the only sphenopsid as yet known from the Devonian of Gondwana, and is currently known from only a small number of specimens collected from the main fish layer/lens (MFL) black shale within the Witpoort Formation (Witteberg Formation, Cape Supergroup) at Waterloo Farm, Makhanda. It is currently interpreted as a small-sized herbaceous plant.    and 'exhibits a novel architecture' that includes apparently plesiomorphic characters, reminiscent of the organisation of the Iridopteridales (including the production of two types of laterals at one node, the location of fertile parts in loose whorls on lateral branches and an organisation of the fertile parts in which they branch several times before bearing distally elongate sporangia). Other characters unambiguously nest Rinistachya within the Sphenopsida (including presence of planate and slightly webbed ultimate appendages and lateral strobili made of successive whorls of fertile leaves with fertile parts located at their axil). This provides strong support for a close relationship between Sphenopsida and Iridopteridales. It is the only known high latitude sphenopsid known from the Devonian, the only other 3 genera, Eviostachya, Hamatophyton and Rotafolia being of palaeotropical provenance.