Figs. 50-55. Fossombronia alaskana Steere & Inoue. 50.SEM micrograph of plant with mature caulocalyx terminating the branch to the right and antheridia on the branch to the left; scale bar = 100 µm. 51. SEM micrograph of a branch bearing a cluster of antheridiaat the apex. Each antheridium (an) is subtended by a triangular scale (arrow); scale bar = 100 µm. 52. SEM micrograph of a female branch found on the same plant as the male branch in figure 50, showing the overarching leaves and apical clusters of archegonia; scale bar = 100 µm. 53. SEM micrograph of a caulocalyx, showing the constricted mouth with distinct keels (arrow) that are characteristic of this species; scale bar = 100 µm. 54. OM micrograph of a leaf; scale bar = 100 µm. 55.OM micrograph of elongate median leaf cells; scale bar = 100 µm. Figs. 50 - 55. from the holotype of F. alaskana, Steere & Inoue 72-360 (NY).