Alsidium seaforthii (Turner) J.Agardh

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 : 230

Alsidium seaforthii (Turner) J.Agardh

Thallus fleshy, reddish, 6–20 cm long, with flattened axes in cross section, 480–500 μm x 260–280 μm in diameter. Main axes branching pseudo-dichotomously; branches covered with alternating opposite arranged ramuli ( Fig. 9 ). Polysiphonous organization, with 8 pericentral cells, 60–85 μm x 50–65 μm in diameter, elongated, arising from a central spherical axial cell (40–50 μm in diameter) ( Fig. 10 ). Medulla with two layers of rounded cells, 45–75 μm in diameter. Cortex with one layer of conspicuously pigmented cells, 12–18 μm in diameter ( Fig. 10 ).

Taxonomic comment: This species and the following species had been treated as species of Bryothamnion until very recently. García-Soto & Lopez-Bautista (2018) presented molecular-based evidence to propose the merger of Bryothamnion within Alsidium . These two species had been assigned to that genus in the past, and so those two names are reinstated.

Figures

FIGURES 6–16. 6. Jania pumila, main axes showing genicula, intergenicula and branching pattern.Scale bar = 5 mm.7–8. Acanthophora spicifera. 7. Habit. Scale bar = 2 cm. 8. Medullary and cortical cells. Scale bar = 70 μm. 9–10. Alsidium seaforthii. 9. Habit. Scale bar = 2 cm. 10. Pericentral, medullary and cortical cells. Scale bar = 100 μm. 11–12. Alsidium triquetrum. 11. Habit. Scale bar = 3 cm. 12. Pericentral and medullary cells. Scale bar = 145 μm. 13–14. Digenea simplex. 13. Habit. Scale bar = 3.5 cm. 14. Pericentral and medullary cells. Scale bar = 110 μm. 15–16. Laurencia intricata. 15. Habit. Scale bar = 2 cm. 16. Superficial cherry bodies. Scale bar = 50 μm.