Chara schultae Casanova, 2023

Casanova, Michelle T. & Karol, Kenneth G., 2023, Charophytes of Australia’s Northern Territory - I. Tribe Chareae, Australian Systematic Botany 36 (1), pp. 38-79 : 68-70

Chara schultae Casanova , sp. nov.

Type: Billabong next to the Darwin River, 4 May 2011, J. Schult t839 (holo: MEL!) .

Monoecious. Plants up to 200 mm high, not much branched, elongate and flexible, not calcified ( Fig. 18 a ). Axes 200– 400 µm in diameter, 2–3× corticated, somewhat tylacanthous, 21–24 cells around ( Fig. 18 d ). Internodes 5–90 mm long. Spine cells solitary, obscure, acute when visible in the youngest internodes. Stipulodes in 1 row, up to twice the number of branchlets, but sometimes obscure, usually up to 1.5 mm long, spreading and narrow, ~50 µm wide ( Fig. 18 c ). Branchlets 8 or 9 in a whorl, ecorticate, 4 or 5 cells long, basal branchlet cell longest, up to half the branchlet length, branchlet end segment a single cell with long subtending bract cells, bract cells 4–6, verticillate, up to 2 mm long ( Fig. 18 c ). Bracteoles 2, up to 0.5 mm long ( Fig. 18 b ). Gametangia conjoined, solitary at the lowest branchlet nodes, rarely at the second node ( Fig. 18 b ). Oosporangia up to 450 µm long, 300–350 μm wide, coronula appressed. Oospores broadly oval, 300–350 µm long, 210–250 µm wide, with 7 or 8 striae of distinct flanges (up to ~10 µm high) ( Fig. 18 e ), although these might not be present in aged oospores ( Fig. 18 h ), the oospore wall appearing smooth ( Fig. 18 f, i ), but minutely granulate ( Fig. 18 j ), basal cell impression up to 50 µm in diameter ( Fig. 18 g ). Antheridia up to 250 µm in diameter. Chromosomes not known.

Distribution

Tropical northern Australia in shallow freshwater waterbodies, rivers and ponds.

Etymology

Named for Julia Schult, charophyte collector in the Northern Territory.

Notes

Chara schultae is a delicate and flexible monoecious species in section Agardhia . It differs from all others by its very long and narrow bract cells and stipulodes, along with obscure spine cells.

Chara schultae is characterised by monoecy, long primary branchlet segments, and an axial cortex where the number of cortical cells is two to three times the number of branchlets in the adjacent whorl. It differs from the similar monoecious C. arnhemensis on the basis of the relative paucity of spine cells, overall longer and more flexible morphology, and larger oospores.

Specimens examined

NORTHERN TERRITORY: Daly River , 2001, S. Townsend p56[-a] ( MEL); Elkedra Station, lagoons on upper Elkedra River , 7 May 1977, T. S. Henshall 1745 (DNA, NT); Hemple Bay, Groote Island , 7 May 1948, R. L. Specht A19 ( AD) .

Figures

Fig. 18. (Caption on next page)