SEM images of the megaspore of Isoetes nana (Ule 98, G), I. weberi (Herter 95840, US), I. quiririensis (Pereira 635, UPCB), I. maxima (Pereira 631, UPCB). A–B Details of the macrosculpture of the megaspore of I. nana A Proximal view B Distal view C Details of the microsculpture of the megaspore of I. nana in distal view showing the terminal ends of anastomosed bars joined forming bacillae or more rarely echinulae D–E Details of the macrosculpture of the megaspore of I. weberi D Proximal view E Distal view F Details of the microsculpture of the megaspore of I. weberi in distal view showing the terminal ends of anastomosed bars joined forming echinulae G–H Details of the macrosculpture of the megaspore of I. quiririensis G Proximal view H Distal view I Details of the microsculpture of the megaspore of I. quiririensis in distal view showing the terminal ends of anastomosed bars joined forming echinulae or rarely bacillae J–K Details of the macrosculpture of the megaspore of I. maxima J Proximal view K Distal view L Details of the microsculpture of the megaspore of I. maxima in distal view showing the terminal ends of anastomosed bars joined forming bacillae. Scale bars: A, B, D, E, G, H, J, K = 10 µm; C, F, I, L = 1 µm.