Meristotheca cylindrica M.L.Núñez-Resendiz, Dreckmann & Sentíes

Resendiz, María Luisa Núñez, Dreckmann, Kurt M., Sentíes, Abel, Wynne, Michael J. & Tejera, Hilda León, 2019, Marine red algae (Rhodophyta) of economic use in the algal drifts from the Yucatan Peninsula, Mexico, Phytotaxa 387 (3), pp. 219-240 : 231

Meristotheca cylindrica M.L.Núñez-Resendiz, Dreckmann & Sentíes

Thallus cartilaginous, reddish dark or purple, 5–30 cm in length, with cylindrical axes in cross section, 380–780 μm in diameter. Main axes and branches branching opposite each other alternately giving the thallus a feathery appearance ( Fig. 27 ). Multiaxial organization with a filamentous medulla and a pseudoparenchymatous cortex ( Fig. 28 ). Medulla composed of several axial filaments, 4.5–7 μm in diameter, running parallel to the longitudinal plane of the axes, with adventitious filaments that connect the cells of the inner cortex of opposite sides. Inner cortex with 5 layers of irregular or stellate cells, 40–80 μm in diameter. Outer cortex with two layers of cells, 9–15 μm in diameter. Cystocarps of 625–864 μm x 480–672 μm in diameter, developing from a pseudoparenchymatous central mass of sterile cells that gives rise to the peripheral gonimoblasts, ( Fig. 29 ).

Figures

FIGURES 17–27. 17. Laurencia intricata. Medullary and cortical cells. Scale bar = 30 μm. 18–19. Yuzurua poiteaui var. gemmifera. 18. Habit.Scale bar = 3cm. 19. Pericentral, medullary and cortical cells. Scale bar = 120 μm. 20–21. Hypnea musciformis. 20. Habit. Scale bar = 2 cm. 21. Medullary and cortical cells. Scale bar = 120 μm. 22–26. Eucheumatopsis isiformis. 22. Habit. Scale bar = 4 cm. 23. Medullary filaments and cortical cells. Scale bar = 460 μm. 24. Mature cystocarp. Scale bar = 110 μm. 25. Tetrasporangium laterally attached. Scale bar = 25 μm. 26. Habit with smooth surfaces. Scale bar = 10 cm. 27. Meristotheca cylindrica. Habit. Scale bar = 4 cm.

FIGURES 28–38. 28–29. Meristotheca cylindrica. 28. Medullary filaments and cortical cells. Scale bar = 140 μm.29. Immature cystocarp. Scale bar = 220 μm. 30–32. Tepoztequiella rhizoidea. 30. Habit. Scale bar = 3.5 cm. 31. Medullary filaments and cortical cells. Scale bar = 90 μm. 32. Tetrasporangia basally attached (arrowhead). Scale bar = 30 μm. 33–34. Gracilaria blodgettii. 33. Habit. Scale bar = 2 cm. 34. Medullary and cortical cells. Scale bar = 140 μm. 35–36. Gracilaria caudata. 35. Habit. Scale bar = 4 cm. 36. Medullary and cortical cells and a mature cystocarp. Scale bar = 310 μm. 37–38. Gracilaria cervicornis. 37. Habit. Scale bar = 3 cm. 38. Medullary and cortical cells. Scale bar = 150 μm.