Chara protocharoides 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 : 67

Chara protocharoides Casanova & Karol, Austral. Syst. Bot. 22: 32 (2014)

[non Chara australis R.Br., Prodr. 346 (1810)]

Protochara australis Womersley & Ophel, Trans. Roy. Soc. S. Australia 71: 311 (1947); Chara australis subsp. estipulodica M.B.Macdon. & Hotchk., Proc. Linn. Soc. New South Wales 80: 282 (1956). Type: Western Australia: In shallow swamp on peneplain of breakaway country between Mingenew and Irwin River coal seam, south-west of Geraldton , 28 Aug. 1947, H.B.S.Womersley s.n. (holo: AD A5917 a!; iso: AD A5917 c!) .

[ Chara australis f. inflata auct. non R.D.Wood, Nova Hedwigia 22: 25 (1972), p.p.]

Dioecious. Plants up to 400 mm high, somewhat branched, variably inflated, uncalcified ( Fig. 17 a ). Axes ecorticate, internodes 10–100 mm long, 0.9–1.5 mm in diameter on living plants (1.2–2 mm when flattened in pressing). Stipulodes completely absent. Branchlets 6 or 7 in a whorl, entirely ecorticate, segments swollen or inflated in shallow water ( Fig. 17 b ), elongate and cylindrical in deep-water populations ( Fig. 17 e ), pinched in at the nodes, similar in diameter to the axes, 14–30 mm long, 3 or 4 cells long including end segment, basal branchlet cell variable in size, ~300 µm long in upper, fertile branchlets, similar to second branchlet segments on sterile branchlets, branchlet end segments unicellular, very small and mucronate, up to 200 µm long, with nodal cells at the base ( Fig. 17 c ), bract cells and bracteoles completely absent from all branchlet nodes. Upper axes somewhat contracted. Gametangia on separate plants, singly and geminate on first and second branchlet nodes, occasionally oosporangia inside the base of the branchlet whorl ( Fig. 17 b, e ). Oosporangia 670–900 µm long × 600–780 µm wide with 6 or 7 stripes of helical cells, coronula cells connivent and blunt, 80 µm high. Oospores black, 490–560 µm long and 310–390 µm wide, almost rectangular in side view, with 4 or 5 striae ( Fig. 17 f ), sometimes flanged, fossa smooth to minutely granulate ( Fig. 17 g ), and impression of the basal cell 80 µm in diameter ( Fig. 17 h ). Antheridia 800–1150 µm in diameter, octoscutate ( Fig. 17 d ). Vegetative reproduction not known; appears to be an annual in temporary water bodies. Chromosomes not known.

Distribution

Grows in permanent, seasonal and temporary freshwater water bodies in Western Australia and the Northern Territory.

Etymology

From the genus name Protochara and the Latin suffix - oides, resembling, in reference to the genus Protochara Womersley & Ophel , for which this species remains the type.

Notes

The large axis diameter, and complete absence of stipulodes, bract cells and bracteoles are the main characteristics that allow this species to be distinguished.

Specimens examined

NORTHERN TERRITORY: Kings Canyon , 12 Dec. 1968, P. K. Latz 362 (DNA, NT); Serpentine Gorge , Dec. 1968, M. Fagg s.n. (DNA); 42 km NE of Helen Springs Homestead , 14 June 2002, P. K. Latz & D. E . Albrecht 21953 (DNA, NT); Elcho Island , Melaleuca Swamp , 17 July 1975, C. Dunlop 3936 (DNA); above Reedy Rockhole , 16 July 1981, P. K. Latz 8796 (DNA). WESTERN AUSTRALIA: small lake near inflow of Lake Leschenaltia , 5 Oct. 2010, M. T. Casanova r812 ( MEL) .

Figures

Fig. 17. Chara protocharoides, (a–d, f–h) from H.B.S.Womersley, 28 Aug. 1947 (AD a5917a), (e) from M.T.Casanova r812. (a) Habit of plant; scale bar: 1 cm. (b) Whorl of antheridial branchlets; scale bar: 1 mm. (c) Branchlet tip with a single end cell; scale bar: 1 mm. (d) Branchlet node and antheridium; scale bar: 0.5 mm. (e) Oogonial branchlet whorl; scale bar: 1 mm. (f) Scanning electron micrograph (SEM) of oospore; scale bar: 200 µm. (g) SEM of detail of oospore wall; scale bar: 20 µm. (h) SEM of impression of end cell; scale bar: 100 µm.