Figure 14-18. 14 SEM micrograph of antheridia, with short, 4-6 seriate stalks and irregularly arranged jacket cells; the antheridium at the right is fully mature and beginning to open. 15 SEM micrograph of a male plant, showing a mixture of mature and immature antheridia. 16 SEM micrograph of a spore, distal face with echinate lamellae interconnected by low ridges. 17 SEM micrograph of spore, in lateral and proximal views, proximal surface showing a distinct triradiate ridge and crowded, dentate cristae. 18 SEM micrograph of spores and bispiralled elaters.