FIGURES 15–22. Reproductive structures of Aphanta asiatica and field plants. Fig. 15. Cross-section of a tetrasporangial sorus (SY94-1), showing immature tetrasporangia (arrowheads) in the cortex. Scale bar = 50 μm. Fig. 16. A spermatangial sporophyll on the distal end of a branchlet (SY134-1). Scale bar = 1 mm. Fig. 17. A spermatangial sporophyll with a sterile margin (SY134-1). Scale bar = 400 μm. Fig. 18. Surface view of a spermatangial sporophyll showing distinct cell appearances (arrowheads) between sorus and the margin (SY134- 1). Scale bar = 20 μm. Fig. 19. Cross-section of a spermatangial sorus (SY134-1), showing tiny spermatangia (arrowhead) cut off from the outer cortical cells. Scale bar = 20 μm. Fig. 20. Field plants of A. asiatica growing on rocks in the subtidal zone. Fig. 21. A clump of thalli collected from Hongtang Bay, Sanya City, Hainan Island, China. Scale bar = 2 cm. Fig. 22. Plants growing on the higher rocks in the intertidal zone usually become pale and dead when exposed to the sun.