Pachymeniopsis lanceolata

D’Archino, Roberta & Zuccarello, Giuseppe C., 2021, Two red macroalgae newly introduced into New Zealand: Pachymeniopsis lanceolata (K. Okamura) Y. Yamada ex S. Kawabata and Fushitsunagia catenata Filloramo et G. W. Saunders, Botanica Marina (Warsaw, Poland) 64 (2), pp. 129-138 : 131

3.2.1 Pachymeniopsis lanceolata ( Figures 3–16 )

Thalli ( Figures 3–10 ) were flattened, 14–35 (60) cm high and 6–15 cm wide, and attached by a discoid holdfast, from which a short ( Figures 5–6, 9–10 ) or nearly non-existent stipe arose ( Figures 3 and 4 ). Thalli were solitary ( Figures 4 and 5 ) or clustered ( Figure 8 ), the blades were broadly lanceolate ( Figures 3, 4 , and 6) or irregularly divided ( Figures 6–8 ). Old thalli became proliferous ( Figures 8 and 10 ). Thalli were purplish-red to brownish, with a membranous texture that became leathery in old plants. Large thalli had a strong chlorine smell. Blades were 200– 600 µm thick ( Figures 11 and 12 ), reaching up to 1 mm in thickness in old specimens. The cortex consisted of anticlinal filaments (6) 8–12 cells long, the cells becoming progressively smaller toward the surface layer of elongate cells ( Figure 12 ). The medulla was composed of sparsely to densely compacted filaments, 2–7 µm in diameter ( Figures 11 and 12 ). Male gametophytes were found in winter, whereas cystocarps and tetrasporophytes were seen in summer. Tetrasporangia ( Figure 13 ) were scattered over the blade (30–53 × 15–21 µm) and were cruciately divided. The carpogonial branch ampullae were monocarpogonial ( Figure 14 ), 45–57 × 29–40 µm. The auxiliary cell ampullae ( Figure 15 ) were 40–46 µm in length and 30–36 µm in width. The auxiliary cell was intercalary in one of the ampullar filaments and had 12 × 7 µm dimensions. Cystocarps ( Figure 16 ) were 100–220 µm in diameter, immersed in the blades and surrounded by a rudimentary pericarp of lax ampullar filaments. The carposporophytes consisted of three synchronously maturing lobes and contained irregularly angular carpospores (15–22 × 10–13 µm).

Figures

Figures 3–16: Pachymeniopsis lanceolata. Habit, vegetative and reproductive morphology. (3–10) Morphological variation of samples collected in Lyttelton (WELT A034375–A034381) and Taranaki (WELT A034374) (Figure 6). Scale bar = 2 cm. (11) Cross-section through a young blade showing the thin anticlinal cortex and a lax medulla composed of sparse periclinal filaments (WELT A034376). Scale bar = 20 μm. (12) Cross-section through a mature blade showing a thick cortex and a medulla composed of densely aggregated filaments (WELT A034380). Scale bar = 20 μm. (13) Tetrasporangia (arrows) borne in and dislodged from the cortex (WELT A034377). Scale bar = 20 μm. (14) A carpogonial branch ampulla. Arrow shows trichogyne (WELT A034381). Scale bar = 20 μm. (15) An auxiliary cell ampulla. Arrow shows auxiliary cell (WELT A034381). Scale bar = 20 μm. (16) mature carposporophytes, the distal globular consolidated gonimolobes borne aloft on a columnar fusion cell into the central cystocarp chamber (WELT A034380). Scale bar = 20 µm.