Charophytes of Australia’s Northern Territory - I. Tribe Chareae Author Casanova, Michelle T. Author Karol, Kenneth G. text Australian Systematic Botany 2023 2023-03-30 36 1 38 79 http://dx.doi.org/10.1071/sb22023 journal article 10.1071/SB22023 1446-5701 10904227 Chara erythrogyna Griff., Not. Pl. Asiat . 2: 278 (1849) Chara griffithii A.Braun in C . F . O . Nordstedt , Abh. Königl. Kon. Akad. Wiss. Berlin 1882: 129 (1883) , nom. illeg. , nom. superfl. Type : East Indies , W . Griffith s.n. (lecto: B fide J . S . Zaneveld , Blumea 4: 167 (1940) , destroyed?; isolecto: BM !; isolecto: L !) . Monoecious. Plants up to 450 mm high, slender, rarely calcified and somewhat spiky in appearance ( Fig. 11 a ). Axes 400–600 µm in diameter, 2× corticated evenly isostichous, 22–24 cells around ( Fig. 11 e ), internodes 15–45 mm long on lower parts, upper parts contracted. Spine cells solitary, only noticable on the younger internodes, rudimentary or absent on older parts, stipulodes in 1 row, up to twice the number of branchlets (18 counted for 12 branchlets), somewhat variable 0.5–1.5 mm long, acute ( Fig. 11 b ). Branchlets 11–14 (or more; Nordstedt 1883 ) in a whorl, ecorticate, 5 or 6 cells long, up to 20 mm long, tapering, basal branchlet cell the longest, branchlet end segments singular ( Fig. 11 c ), as narrow as the bract cells, bract cells 6–9, verticillate on all branchlet nodes, up to 1.5 mm long, acute ( Fig. 11 f ). Bracteoles 2, shorter than the bract cells. Gametangia conjoined, sejoined, solitary or geminate at the branchlet nodes ( Fig. 11 d , f ). Oosporangia 550–700 µm long, coronula cells very small, apressed, bractlet present when sejoined from antheridia. Oospores black, 375 –420 µm long, 265–290 µm wide, with 8 or 9 striae of prominent ridges ( Fig. 11 g ), the oospore wall smooth or unevenly maculate with rows of small indentations (‘obscurely granulate’ sensu Wood and Imahori 1964 ) ( Fig. 11 h , j ), basal cell impression 36–76 µm in diameter ( Fig. 11 i ). Antheridia up to 700 µm in diameter, scarce, sejoined or conjoined. Chromosomes not known. Distribution In freshwater lakes and wetlands in South-East Asia, Northern Territory around Darwin, Elcho Island . Etymology From Greek erythro- ‘red’, and gynos ‘pertaining to female organs’, named for the bright colour of the young oosporangia. Notes The type material was collected in South-East Asia, deposited in BM , with fragments in L . The Australian material has similarly geminate, conjoined and sejoined gametangia, similar-sized oosporangia, coronula and oospores and similar vegetative morphology. However, the oospores on Australian material differ from Indian material, which have a minutely figured oospore with a tiny basal cell impression (36 μm). Australian material fits well with Braun’s description of the type material (even to the size of the end segments of branchlets and relative scarcity of antheridia) ( Nordstedt 1883 ). Fig. 11. ( Caption on next page ) Fig. 11. Chara erythrogyna , ( a , g–j ) from specimen G.O.Allen 158 (BM), ( b–f ) from specimen M.T.Casanova r752 (MEL). ( a ) Habit of whole plant, scale bar: 10 cm. ( b ) Sterile whorl of branchlets, scale bar: 1 mm. ( c ) Whorl of fertile branchlets, scale bar: 1 mm. ( d ) Fertile node with geminate oogonia, scale bar: 200 µm. ( e ) Transverse section of axis, scale bar: 0.5 mm. ( f ) Fertile node with geminate, conjoined oogonia and antheridia, scale bar: 5 mm. ( g ) Scanning electron micrograph (SEM) of oosporangium in side view, scale bar: 100 µm. ( h ) SEM of detail of oospore wall, scale bar: 20 µm. ( i ) SEM of fine detail of oospore wall, scale bar: 50 µm. ( j ) SEM of basal cell impression on oospore, scale bar: 2 µm. Braun thought the name Chara erythrogyna was inappropriate (since the gametangia were only red in the juvenile state) and so published the superfluous replacement name Chara griffithii (Braun, unpubl. data, cited in Nordstedt 1883 ). Chara erythrogyna is distinguished from all other Australian species with corticated axis and naked branchlets by its gametangial arrangement. This is usually noticeable as frequently geminate oosporangia or oospores, and inconspicuous and rare antheridia, occasionally conjoined with an oosporangium. Specimens examined NORTHERN TERRITORY: Yirrkala , 11 Aug. 1948 , R . L . Specht A75 ( AD ); Manton Dam Recreation Area , in water ~ 50 cm deep, 5 Sep. 2010 , M . T . Casanova r752 ( MEL , NY ); shallow lagoon in Melaleuca – Mimusops thicket, Nightcliff Agricultural Area , 21 Apr. 1961 , R . D. Wood & N . Eddy 61-4-21-4 A ( AD ); Elcho Island , 13 July 1975 , P . K . Latz 6208 (DNA); Port Darwin , 9 Apr. 1896 , T . B . Blow A101 ( BM ). INDIA : shallow pond, Saharanpur District , United Provinces , 19 Sep. 1926 , G . O . Allen 10 ( BM ); small pond Saharanpur , United Provinces , 31 Oct. 1926 , G . O . Allen 158 ( BM ); Saharanpur United Provinces , G . O . Allen 90 ( BM ) .