Polysiphonia delicata Díaz-Tapia

Piñeiro-Corbeira, Cristina, Maggs, Christine A., Rindi, Fabio, Bunker, Francis, Baldock, Lin & Díaz-Tapia, Pilar, 2020, Molecular assessment of the tribes Streblocladieae and Polysiphonieae (Rhodomelaceae, Rhodophyta) in the British Isles reveals new records and species that require taxonomic revision, Cryptogamie, Algologie 20 (8), pp. 55-72 : 62-63

Polysiphonia delicata Díaz-Tapia

MOLECULAR IDENTIFICATION

In total, 11 sequences have previously been published for Polysiphonia delicata from Spain and Australia, which represent two haplotypes, one found only in Australia and the other in both countries ( Fig.2 ). The newly determined sequence for an English specimen was identical to sequences from Spain and Tasmania. Polysiphonia delicata was placed in the rbc L phylogeny in a highly supported clade with P.stricta (Mertens ex Dillwyn) Greville , the generitype, and eight other species. Polysiphonia delicata was sister to P. radiata Díaz-Tapia , but this relationship received low support ( Fig. 2 ). Divergence between this pair of species was 4.1-4.2%.

MORPHOLOGICAL OBSERVATIONS

Thalli forming discrete tufts, 2 cm high ( Fig. 7A ), pink in colour and flaccid in texture. Axes ecorticate, with four pericentral cells ( Fig. 7B ). Prostrate axes bearing unicellular rhizoids in open connection with the pericentral cells ( Fig. 7C ). Erect axes 80-120 µm in diameter, composed of segments 1.5-3.5 L/D. Trichoblasts absent. Plants dioecious. Mature cystocarps slightly urceolate, 430-650 µm high and 260-400 µm in diameter ( Fig. 7D ).

Figures

FIG. 2. — Phylogenetic tree estimated with ML analysis of rbcL sequences. Values at nodes indicate bootstrap support (BP) (only shown if ≥70). Species analysed in this study are grey-shaded and species or haplotypes found in the British Isles are in bold. For P. morrowii Harvey, the number (n) of sequences available for each haplotype is indicated. Codes for countries/regions: AD, Adriatic Sea; AR, Argentina; AUS, Australia; BC, British Columbia; CH, Chile; EN, England; FR, France; GUE, Guernsey; IR, Ireland; JA, Japan; KO, Korea; LG, Ligurian Sea; NZ, New Zealand; PO, Portugal; SP, Spain.

FIG. 7. — Polysiphonia delicata Díaz-Tapia: A, habit; B, cross-section of an axis with four pericentral cells; C, rhizoid in open connection with a pericentral cell; D, cystocarp. Scale bars: A, 10 mm; B, 20 µm; C, 200 µm; D, 50 µm.