Fig. 3From: Further study of Late Devonian seed plant Cosmosperma polyloba: its reconstruction and evolutionary significanceInterpretative diagram showing architecture of bifurcate (a) and trifurcate (b) fronds of Cosmosperma polyloba. The connection between trifurcate frond and fertile rachises bearing synangia (dashed lines with a question mark) is speculative. Abbreviations: pr, primary rachis; sr, secondary rachis; mr, median rachis; tr, tertiary rachis; qr., quaternary rachis; fr, fertile rachis; pn, pinnuleBack to article page