Laurencia microcladia Kützing

Popolizio, Thea R., Schneider, Craig W., Jongbloed, Walter M., Saunders, Gary W. & Lane, Christopher E., 2022, Molecular analysis resolves the taxonomy of the Laurencia complex (Rhodomelaceae, Ceramiales) in Bermuda and uncovers novel species of Chondrophycus and Laurenciella, Cryptogamie, Algologie 20 (1), pp. 1-30 : 7

Laurencia microcladia Kützing

( Figs 2, 3)

Tabulae phycologicae: 22, pl. 60, figs b, c (1865).

DISTRIBUTION. — Bermuda, Florida, Central America, Caribbean, Brazil, Mediterranean, Azores, Canary Islands, Cape Verde Islands, North Africa, Arabian Gulf, Singapore, Vietnam, Polynesia, Samoa (Guiry & Guiry 2021).

DESCRIPTION

Plants to 6.5 cm tall, fleshy, green to deep purplish-red, often with distinct purple-red branchlet tips, forming clumps with several associated upright axes; individual axes narrowly pyramidal or sometimes with secondary branches not varying much in length from base to tip of main axes; main axes to 0.5 mm diam. with discoidal holdfasts; densely irregularly branched in all directions, some branches clustered creating a whorled appearance; branchlets clavate to narrowly turbinate, to 2 mm long; densely clustered ultimate branches imparting a verrucose appearance. Vegetative axes with 4 pericentral cells; secondary pit connections present; in surface view cortical cells 15-50 µm diam., irregularly rounded to rounded rectangular in upper branch regions, elongate-angular to elongate-ovoid below; corps en cerise present; outer cortical cell projections absent. In transverse section, outer cortical cells appearing subquadrate or campanulate to ovoid, 12-36µm diam.; medullary cells 45-120 µm diam. Branch tips with deep apical pits, trichoblasts emerging from the pits, dichotomously branched to 6 or more orders, and expanding in diam. distally.Tetrasporangia arranged parallel to axis ( Saito 1967, p. 71), spherical to slightly ovoid, 60-100 µm diam. ( Fig. 3B, C); cystocarps urn-shaped, situated near branchlet tips, 600-820 µm diam. ( Fig. 3D), carposporangia obpyriform, 30-60 µm diam. and 80-125 µm long. Spermatia formed in dense fascicles issued from lower portions of trichoblasts, spherical to obovoid, 2-3 µm diam.