Chara lucida (A.Braun) Casanova & Karol, Austral. Syst. Bot.

Casanova, Michelle T. & Karol, Kenneth G., 2023, Charophytes of Australia’s Northern Territory - I. Tribe Chareae, Australian Systematic Botany 36 (1), pp. 38-79 : 64

Chara lucida (A.Braun) Casanova & Karol, Austral. Syst. Bot. 22: 28 (2014)

( Fig. 10 .)

Chara australis var. lucida A.Braun in C. F. O. Nordstedt, Abh. Königl. Akad. Wiss. Berlin 1882: 106 (1883). Type: Northern Territory: Victoria River , s. dat., F.Mueller 5 (lecto: L!; isolecto: LD!, fide J.S.Zaneveld, Blumea 4: 127 (1940); isolecto: MEL); Northern Territory: Baines Creek , 1856, F.Mueller s.n. (remaining syn: LD!) .

Chara australis f. tenerior Zaneveld, Blumea 4: 127 (1940). Type: Gulf of Carpentaria, 1856, F. Mueller s.n. (holo: B [destroyed; Wood (1965: 276)]; iso: L, LD) .

Chara australis var. lucida f. typica Zaneveld , Blumea 4: 126 (1940), nom. inval.

Chara corallina f. lucida R.D.Wood , Taxon 11: 13 (1962), nom. inval.

Chara corallina f. lucida R.D.Wood, Rev. Characeae 1: 275 (1965), nom. inval., nom. alt.

Chara lucida R.D.Wood, Rev. Characeae 1: 769 (1965), nom. inval., nom. alt.

Dioecious. Plants flexible, transparent, often in tangled clumps, up to 200 mm tall, uncalcified ( Fig. 15 a ). Axes 0.35–0.7 mm wide (when flat and dried, narrower in fresh material), ecorticate, internodes 8–20 mm long, generally much shorter than the adjacent branchlets ( Fig. 15 a ). Stipulodes in a single row, 6–12 in total, usually fewer apparent, up to 0.5 mm long. Branchlets 6 or 7 in a whorl, ecorticate, 11–50 mm long, 0.3–0.6 mm wide, 4 or 5 cells long, basal branchlet cell up to 10 mm long ( Fig. 15 b ), branchlet end segments small, conical and acute, sometimes subtended by 1 or 2 bract cells, bract cells obscure or short ( Fig. 15 c ). Bracteoles obscure or short, occasionally up to 0.5 mm long. Fertile parts sometimes somewhat contracted with shorter branchlets and internodes. Specimens with only fertile branchlets were distinguished as form tenerior but recent collections (e.g. M. T.Casanova r758) have both long sterile and short fertile branchlets on the same plant. Gametangia sessile inside the base of the whorl and solitary, geminate or clustered at the lowest 1 or 2 branchlet nodes ( Fig. 15 e ). Oosporangia 0.9 mm long, 0.5 mm wide, coronula cells very short, obtuse. Oospores black, cylindrical, 600–670 µm long, 380–400 µm wide, 7 or 8 striae of low ridges ( Fig. 15 f ), ornamentation smooth to minutely granulate ( Fig. 15 g ), basal-cell impression 120–150 µm in diameter at the widest part, edges 95–100 µm long ( Fig. 15 h ). Antheridia from 400 to 850 µm in diameter. Vegetative reproduction not known. Chromosomes not known.

Distribution

Tropical and subtropical Queensland, Western Australia and the Northern Territory in freshwater dams, ponds, still rivers and lagoons. Also occurs in Papua New Guinea.

Etymology

From the Latin ‘ lucidus ’, meaning shining, clear, transparent. Zaneveld (1940) and Wood (1971) thought this referred to a shiny surface on the pressed specimens, but that feature is neither obvious nor consistent. More likely, it refers to the clear and transparent, almost colourless appearance ( Nordstedt 1883) of the pressed type material.

Notes

The species can be distinguished as a totally ecorticate Chara species with narrow axes, distinguished from narrower morphs of C. australis by the short internodes in comparison with the branchlets. Distinguished from C. evanida by dioecy and the single end cells on the branchlet tips. Chara lucida forms tangled masses in warm waters, compared with the upright, turgid stems of C. australis in colder, deeper waters.

Specimens examined

NORTHERN TERRITORY: Mary-Ann Dam , 6 km NNE Tennant Creek, 7 Nov. 1988, P. K. Latz 10993 (DNA, NT); Duckponds Waterhole, 80 km SE of Lajamanu, 12 May 2010, C. Brock 900 (DNA, NT); Swamp SW of Elizabeth Downs Homestead, 23 June 1977, L. A. Craven 4375 (DNA); Arafura Swamp , 20 May 1990, M. J. Clarke 2259 (DNA); Cathedral Billabong , 20 July 1983, P. McBride 8843 (DNA); Connelly’s Camp Waterhole, Benmara Station , 6 May 1984, B. W. Strong 226 (DNA); Lake Ucharonidge , 22 Apr. 1991, D. J. Parsons 136 (DNA); Manton Dam recreation area, 5 Sep. 2010, M. T. Casanova r758 ( MEL, NY); roadside borrow-pit on Arnhemland Highway , M. T. Casanova r784 ( B, MEL, NY); SW of Elizabeth Downs, Daly River region, 23 June 1977, L. A. Craven 4375 ( CANB); Oenpelli, 10 Oct. 1948, R. L. Specht A110 ( AD, MEL, NY); Katherine, 14 Feb. 1961, H. S. McKee 8427 ( CANB); Arafura Swamp, near Glyde River crossing, 23 Sep. 1998, I. D. Cowie & C. P . Mangion 7985 (DNA); Koolpinyah Station , 8 May 1996, C. R. Michell & J. L .Egan 108 (DNA). QUEENSLAND: in Lagoon, Magoura Station , 18 July 1977, L. A. Craven 4782 ( CANB) .

Figures

Fig. 10. Chara duriuscula, (a, d, f) from M.T.Casanova r773 (MEL), (b, i–k) from the holotype specimen F. v. Mueller 2 (LD), (c, g–h) from M.T.Casanova r781 (MEL), (e) from M.T.Casanova r774. (a) Habit of whole plant, scale bar: 10 mm. (b) Fertile branchlet whorl, scale bar: 1 mm. (c) Transverse section of axis, scale bar: 200 µm. (d) Fertile node with oosporangium, antheridium, bracteoles and bract cells, scale bar: 1 mm. (e) Whorl of stipulodes below the branchlets, scale bar: 1 mm. (f) Whorl of fertile branchlets, scale bar: 5 mm. (g) Young axis with spine cells. (h) Light micrograph of an oospore with evidence of calcification, ~500× magnification. (i) Scanning electron micrograph (SEM) of oospore with nine striae and a granulate fossa wall, scale bar: 100 µm. (j) SEM of oospore wall, scale bar: 20 µm. (k) SEM of pentagonal basal cell, scale bar: 50 µm.

Fig. 15. Chara lucida, (a–d) from M.T.Casanova r784, (e) from L.A.Craven 4782 and (f–h) from the Victoria River specimen F. v. Mueller 5. (a) Habit of whole plant; scale bar: 5 mm. (b) Fertile oogonial whorl, scale bar: 5 mm. (c) Final two branchlet cells, scale bar: 0.5 mm. (d) Oosporangium; scale bar: 100 µm. (e) Fertile antheridial branchlet whorl, scale bar: 5 mm. (f) Scanning electron micrograph (SEM) of oospore; scale bar: 200 µm. (g) SEM of detail of oospore wall; scale bar: 50 µm. (h) SEM of impression of baseal cell on the oospore; scale bar: 100 µm.