Chara porteri Casanova, Austral. Syst. Bot. 22: 30 (2014)

Type: Western Australia: Ethel Creek Claypan, Pilbara Biological Survey site 041, T2, 1 June 2004, M. N. Lyons & D. A . Mickle 3077 (holo: PERTH!; iso: MEL!) .

Dioecious. Plants somewhat inflated and turgid, sometimes calcified, up to 150 mm tall, somewhat densely branched, with incurved branchlets in shallow water (Fig. 16 a). Axes 0.7 mm wide (up to 1 mm on pressed specimens), ecorticate. Internodes 8–25 mm long, shorter and somewhat contracted at the apices. Rarely internodes appear 2 cells long (Fig. 16 g). Stipulodes in a single row when present, frequently obscure or absent, up to 6 in a whorl. Branchlets 6 in a whorl, sometimes made up of a few elongate branchlets and some dwarf branchlets, particularly at the apices, ecorticate, 8–15 mm long, 0.4–0.6 mm wide, 3 or 4 cells long, basal branchlet cell up to 6 mm long, usually the longest cell in the branchlet (Fig. 16 b, d), branchlet end segments small, conical and acute, occasionally subtended by bract cells (Fig. 16 c, e), bract cells usually obscure, up to 0.2 mm long, or absent. Bracteoles obscure, up to 0.2 mm long, or absent. Gametangia on separate plants, sessile inside the base of the whorl, and solitary, geminate or clustered at the lowest 1 or 2 branchlet nodes (Fig. 16 g, h). Oosporangia 0.6–0.75 mm long, 0.5 mm wide, coronula cells short, somewhat spreading, slightly apiculate (Fig. 16 f). Oospores black, cylindrical, 470–525 μm long, 250–350 μm wide, 5 or 6 striae of wide ridges (pachygyra) (Fig. 16 i), ornamentation smooth to minutely granulate (Fig. 16 j), basal-cell impression 100–120 μm in diameter at the widest part, edges 70–76 μm long, rarely 6-sided (Fig. 16 k). Antheridia octoscutate, up to 850 μm in diameter (Fig. 16 g). Vegetative reproduction not known. Chromosomes n = 14 (M. T.Casanova r416).

Distribution

Occurs in freshwater temporary wetlands (claypans and riparian overflows) in the semi-arid regions in central Australia.

Etymology

Named in honour of John L. Porter, who collected the first herbarium material of this species, from the Paroo region in New South Wales.

Notes

Specimens are distinctly turgid and brightly festooned with gametangia, with incurved branchlets. The oospores have markedly enlarged striae (pachygyra).

Specimens examined

NORTHERN TERRITORY: Joker Gorge, Arltunga, 20 May 1986, G. Leach 736 (DNA); Western Tanami Desert, Wilson Creek floodout, 29 Apr. 2004, I. Cowie & A . Duguid 10241 (DNA, NT); 7 km SSW of Newhaven Homestead in a seasonal freshwater lake, 2 Oct. 2000, P. K. Latz 16815 (DNA NSW, NT); Wonkari Waterhole, S side of Petermann Ranges, 20 Jan. 1968, J. R. Maconochie 685 (DNA, NT); Duck pond outstation at Merrina Waterhole, 5 Sep. 1986, G. Leach 808 (DNA, NT) . WESTERN AUSTRALIA: Coolarin Pool, Pilbara Survey PSW033, 18 May 2004, M. N. Lyons & D. A . Mickle 3061 (PERTH) .