Sargassum ilicifolium (Turner) C.Agardh

Santiañez, Wilfred John E., Lastimoso, John Michael L., Hoshino, Masakazu, Villafuerte, Brix Nester Q., Kogame, Kazuhiro & Gavino C. Trono, Jr, 2023, Molecular-assisted taxonomic study on the Sargassum C. Agardh (Fucales, Phaeophyceae) in northwestern Luzon, Philippines, Cryptogamie, Algologie 20 (7), pp. 127-142 : 132

Sargassum ilicifolium (Turner) C.Agardh

Fucus ilicifolius Turner , Fuci sive plantarum fucorum generi a botani - cis ascriptarum icones descriptiones et historia: 113 ( Turner 1807).

Sargassum aquifolium sensu Coppejans et al. (2017) , non Sargassum aquifolium (Turner) C.Agardh.

Sargassum crassifolium sensu Ang & Trono (1987) ; Trono (1992, 1997); Noiraksar & Ajisaka (2008); Coppejans et al. (2010); Santiañez & Trono (2013), non Sargassum crassifolium J.Agardh.

Sargassum cristaefolium sensu Ang & Trono (1987) ; Trono (1992, 1997); Modelo & Umezaki (1995), non Sargassum cristaefolium C.Agardh.

Sargassum turbinarioides sensu Trono (1997) , non Sargassum turbinarioides Grunow.

TYPE LOCALITY. — Indonesia. Sunda Strait ( Silva et al. 1996: 676).

SPECIMENS EXAMINED. — Philippines. Pangasinan, Bolinao, Malilnep , 9.III.2019, leg. A.C. Calaguing ( MSI [ MSI29137 ]); Ilocos Sur, San Esteban, Apatot , 26.IX.2018, leg. W.J.E. Santiañez ( MSI [ MSI29151 , MSI29152 , MSI29156 , MSI29160 ]); Ilocos Sur, Santiago, Ambucao , 26.IX.2018, leg. W.J.E. Santiañez ( MSI [ MSI29174 , MSI29176 , MSI29186 , MSI29187 , MSI29189 ]); La Union, Balaoan, Almeida , 27.IX.2018, leg. W.J.E. Santiañez ( MSI [ MSI29196 ]); La Union, Balaoan, Paraoir , 27.IX.2018, leg. W.J.E.Santiañez ( MSI [ MSI29199 , MSI29200 , MSI29201 ]); La Union, San Fernando , Lingsat-MPA, 27.IX.2018, leg. W.J.E. Santiañez ( MSI [ MSI29206 ]).

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

DESCRIPTION

Thallus golden to dark brown in color, to 45 cm long, holdfast conical to discoid ( Fig. 4 ). Main axes terete to slightly compressed, to 3 mm in diameter, warty, usually covered with epiphytes; secondary axes also terete or slightly compressed, smooth, slightly thinner than main axes ( Fig.4C ). Blades vertically attached, to 4 cm long, somewhat leathery or crisp when dried ( Fig.4D ); blade shape highly variable but mostly lanceolate to oblanceolate in vegetative branches ( Fig. 4C, D, G ), those in reproductive branches oblanceolate to obovate; apex often attenuate or acute, sometimes round or obtuse ( Fig. 4 E-G); base usually asymmetrically cuneate; margin serrate to biserrate, sometimes erose or repand; some blades in terminal portion of the axes with duplicated apices perpendicular to the surface, some appearing turbinarioid ( Fig. 4 C’; Fig. 4G : arrowhead); midrib thin, apparent from to 2/3 of the blade length, sometimes percurrent; cryptostomata embedded and randomly scattered on the surface of the blade; petiole short to 3 mm long, flattened or cylindrical, with occasional spine-like protrusions. Vesicles smooth, globose, to 5.4 mm in diameter, sometimes ribbed to mucronated or phyllocystic with few cryptostomata; stalks short, to 3 mm long ( Fig. 4D, F ). Dioecious, receptacles closely associated with blades and vesicles, arranged racemosely ( Fig. 4E, F ); female receptacles compressed to flattened with dentate margin ( Fig. 4E ), male receptacles cylindrical and lumpy ( Fig. 4F ).

Figures

FIG. 1. — Map of the Philippines showing collection localities and distribution of specimens of Sargassum C.Agardh used in this study.

FIG. 4. — Sargassum ilicifolium (Turner) C.Agardh from northwestern Philippines: A, top view of some S. ilicifolium thalli growing in the shallow subtidal of Arosan, Bolinao, Pangasinan; B, in situ photograph of a young S. ilicifolium thalli showing the wavy and toothed and occasionally “duplicated” blades (arrowhead); C, pressed herbarium specimen of S. ilicifolium from Ilocos Sur, Philippines. Portion of an axis showing several turbinariod blades (C’: arrowheads); D, portion of an axis showing small, ribbed vesicles (arrowheads) growing together with blades of various shapes; E, fertile portion of a female plant showing the com- pressed to flattened and toothed female receptacles (arrowheads) that are closely associated with blades; F, portion of a male plant showing terete receptacles (arrowheads) that are closely associated with vesicles (arrows) and blades; G, variability of shape and form of S. ilicifolium blades, those with double rows of teeth, duplicated apical margins, and with cup-shaped/turbinarioid apices are indicated with double arrowheads, arrow, and arrowhead, respectively. Scale bars: C, 5 cm; C’, E-G, 1 cm; D, 2 cm.