Sargassum aquifolium (Turner) C.Agardh

Fucus aquifolius Turner, Fuci sive plantarum fucorum generi a botanicis ascriptarum icones descriptiones et historia: 111 (Turner 1807).

Sargassum kushimotense sensu Trono (1992, 1997); Santiañez & Trono (2013), non Sargassum kushimotense Yendo.

TYPE LOCALITY. — Indonesia. Sunda Strait (Silva et al. 1996).

SPECIMENS EXAMINED. — Philippines. Ilocos Sur, San Esteban, Apatot, 26.IX.2018, leg. W.J.E. Santiañez (MSI [MSI29154]); La Union, Balaoan, Almeida, 27.IX.2018, leg. W.J.E. Santiañez (MSI [MSI29195]); La Union, Balaoan, Paraoir, 27.IX.2018, leg. W.J.E. Santiañez (MSI [MSI29204]).

DISTRIBUTION IN NORTHWESTERN LUZON. — Ilocos Sur, La Union, and Pangasinan (Fig. 1).

DESCRIPTION

Thallus golden brown when fresh (Fig. 3A), drying dark brown, to 42 cm long, attached to the substrate by a conical to discoid holdfast (Fig. 3B, C). Main axes smooth, slightly compressed, short, to 3 mm long, giving rise to several compressed secondary axes, 2.5 mm wide (Fig. 3C). Blades linear-lanceolate to linear-oblanceolate, narrowed towards blunt or acute apices, mostly less than 36 mm long, 8 mm wide; margins serrate-dentate; stalk short, base asymmetrical; midrib apparent, slightly elevated, fading near the tips; cryptostomata prominent, elevated, scattered but tending to be arranged in rows in narrow blades (Fig. 3B, D). Vesicles large, ovoid to obovoid, 5 mm wide, 7 mm long; tips rounded to pointed, some mucronate; stalks compressed, winged to foliaceous, often as long as vesicles (Fig. 3D). Young receptacles densely clustered, short, compressed to slightly flattened (some somewhat triquetrate, others twisted), often with sharp teeth.