A revision of Chara sect. Protochara, comb. et stat. nov. (Characeae: Charophyceae)

Additional keywords: Chara australis, Chara stuartiana, Chara lucida, Chara protocharoides, Chara porteri, Protochara, systematics, Tolypellopsis.

Charophytes (members of the extant family Characeae, Charophyceae) are submerged water plants that grow in fresh, brackish and saline water throughout the world. They are distinguished from other aquatic macrophytes on the basis of their overall simple morphology (consisting of essentially uniseriate, branched filaments of cells), their unique reproductive organs (antheridia producing motile sperm cells, and oogonia or oosporangia containing a non-motile egg cell), and distinctive oospores patterned with helical sutures. The genus Chara L. is characterised by a five-celled coronula on the oogonium (oosporangium), placement of the oogonium above the antheridium where they occur together, whorls of accessory cells below the branchlet whorls (stipulodes) and essentially monopodial branchlet structure. The family Characeae was revised for Australia by Wood (1971); however, Wood’s revision resulted in an unusable taxonomy (Casanova 2005, 2009) and recent studies have shown that the lumping of Australian species with those in the northern hemisphere, and the delineation of numerous subtaxa (varieties, forms) do not represent reality, or enhance utility. There are many more species in Australia than were recognised by Wood (1971) (Casanova 2005, 2009, 2013; García and Chivas 2006) and current advances in charophyte taxonomy, including investigation of oospore morphology with scanning electron microscopy, have allowed a new approach to the systematics of this group.

Traditionally (in what has been termed the Braun–Wood taxonomy, Proctor 1980), the genus Chara has been divided into two groups, defined on the basis of the number of stipulode whorls. These groups have been variously treated as subgenera or sections by different authors (see Kützing 1843; Nordstedt 1883; Zaneveld 1940; Wood 1962; Wood and Imahori 1965; Proctor 1980). Current taxonomy recognises two subgenera, namely, subg. Chara and subg. Charopsis (Kütz.) Leonh. Within subg. Charopsis, the following two sections are currently recognised, following Wood and Imahori (1965): sect. Charopsis (totally ecorticate) and sect. Agardhia R.D.Wood (corticated axes, ecorticate branchlets), with Chara braunii C.C.Gmel. being the type of subg. and sect. Charopsis. However, phylogenetic analysis places C. braunii close to C. muelleri A.Braun, which is in sect. Agardhia (Meiers et al. 1999; McCourt et al. 2000). The remaining totally ecorticate Chara species are morphologically and phylogenetically (McCourt et al. 2000) more similar to each other than to C. braunii; however, a group comprising these ecorticate species, without C. braunii, has no name under the rules of the ICN (McNeill et al. 2012). The members of this group have ecorticate axes and branchlets, and have a relatively simple morphology (compared with corticated species in subgenus Chara). Some of these species have, in the past, been allocated to different genera (e.g. Charopsis Kütz., Nitella C.Agardh, Nitellopsis Hy, Tolypellopsis (Leonh.) Mig. and Protochara Womersley & Ophel). The first member of the group to be described was Chara corallina Klein ex Willd., a monoecious species first collected in India (Willdenow 1805). Soon after, a dioecious species was described from Australia, C. australis R.Br. (Brown 1810). Kützing (1857) placed Brown’s C. australis in the genus Nitella as N. australis (R.Br.) Kütz., described N. stuartiana Kütz. on the basis of more robust material collected from Tasmania, and illustrated both species. In a summary of all the taxa in the subgenus, presented by Nordstedt (1883), Brown’s C. australis was retained without further description, and N. stuartiana was placed in synonymy of that species. From a relatively small number of specimens, an additional six taxa at different ranks were also recognised, including C. australis var. lucida A.Braun, C. australis var. nobilis A.Braun, C. australis subsp. plebeja (R.Br. ex A.Braun) A.Braun, C. australis var. vieillardii A.Braun, C. corallina and C. wallichii A.Braun. The other ecorticate Chara species included in this group by Nordstedt (1883), C. braunii, will not be dealt with in the present study.

Zaneveld (1940) treated C. australis and C. australis var. nobilis as synonymous, but distinguished northern Australian and New Caledonian specimens as different forms of C. australis var. lucida: i.e. f. typica Zaneveld, nom. inval., f. tenerior Zaneveld and f. vieillardii (A.Braun) Zaneveld. Womersley and Ophel (1947) erected the genus Protochara to accommodate a totally ecorticate taxon from Western Australia, Protochara australis Womersley & Ophel, and transferred Nitellopsis inflata Fil. & G.O.Allen ex Fil. to that genus as Protochara inflata (Fil. & G.O.Allen ex Fil.) Womersley & Ophel. Filarszky (1934) also described a species with morphological similarities to C. australis, from Indonesia, as Tolypellopsis simplicissima Fil.

In the first experimental breeding study in the Characeae, Macdonald and Hotchkiss (1956) found that female Chara australis and a specimen from New South Wales identified by H. B. S. Womersley as male Protochara australis were inter-fertile to the point of oospore production, and so amalgamated C. australis and P. australis, separating material that had been called P. australis as a new subspecies, C. australis subsp. estipulodica M.B.Macdon. & Hotchk. In amalgamating Protochara australis with Chara, they also included P. inflata in Chara, as C. inflata (Fil. et G.O.Allen ex Fil.) M.B.Macdon. & Hotchk. Subsequently, on the basis of reproductive morphology and nucleotide sequences, García and Karol (2004) recognised Protochara inflata as a species of Lamprothamnium J.Groves, L. inflatum (Fil. & G.O.Allen ex Fil.) Adr.García & Karol. Wood (1962) amalgamated most of the members of subg. Charopsis into a single species, C. corallina, and delineated several infraspecific taxa, some of which were not validly published (cf. Art. 41.5 of the ICN; McNeill et al. 2012). These were subsequently treated as both forms and varieties of C. corallina, as well as being treated at ‘microspecies’ rank (equivalent in rank to Wood’s forms as well as his ‘monotypic’ varieties and species, i.e. those lacking subordinate taxa) by Wood and Imahori (1965). Infraspecific taxa are treated in the main body of the monograph, with alternative ‘microspecies’ status presented in the Microspecies Appendix at the end of the work. These names are here treated as invalid, alternative names under Art. 36.2 of the ICN (McNeill et al. 2012). Wood (1971) later revised his taxonomy for Australian material, delineating C. corallina var. corallina as those specimens with cylindrical branchlet segments, and C. corallina var. nobilis for those specimens with inflated branchlet segments. Within C. corallina var. nobilis, he tentatively recognised the following four forms: nobilis, inflata, simplicissima and stuartiana. These formae names are here treated as invalid provisional names under Art. 36.1 of the ICN (McNeill et al. 2012).

In the present study, the type material of all the Australian species and their close relatives, as well as more than 200 specimens from field collections and herbaria, were examined to determine the status and morphological limits of the species previously included in Chara subg. Charopsis sect. Charopsis (excluding C. braunii).

Chara species grow as totally submerged water plants, rooted in the sediment by colourless rhizoids, with a photosynthetic axis in the water column. The axis consists of single-celled internodes and whorls of multicellular branchlets, on which the reproductive structures are borne. The axes look very similar to submerged flowering plants, and can be confused with species of Myriophyllum L. Species of Chara in this group are entirely ecorticate, i.e. with no cortex on the axis or branchlets, and, in general, have little in the way of ‘accessory cells’ (i.e. stipulodes, bract cells or bracteoles). Thus, there are few morphological characteristics on which to separate species, which has led to the current taxonomic confusion. They are, in general, somewhat large, with robust axes and spreading whorls of branchlets. The antheridia and oogonia are typical of the genus, but large (up to 1 mm long) in comparison with some other species, and visible to the naked eye. The antheridia are usually bright orange, and the oogonia have few circumvolutions of the enveloping spiral cells and very small, apiculate coronula cells. Their persistent reproductive units (oospores) are among the largest recorded for Australian charophytes, but with relatively few striae (spiral sutures), and some species accumulate starch in the lower and rhizoidal nodal cells (bulbils), which allows them to persist vegetatively. The major characteristics used to separate species in this group are sexuality (monoecious v. dioecious), development and abundance of accessory cells, axis and branchlet diameter and length, characteristics of the branchlet nodes and oospore morphology. They are distinguished from similar species of Lamprothamnium by the presence, in Lamprothamnium, of gyrogonites (calcified covering on the oospore), rounded coronula cells, downward pointing stipulodes and verticillate bract cells.

Approximately 200 fresh, pressed and spirit-preserved specimens of charophytes in Australian and overseas herbaria and several private collections were examined for the present study, including 15 specimens designated as type material of species, subspecies, varieties or forms within the group. Each specimen was allocated a letter–number combination (p###, r###, t### or v###), so that all data obtained and stored for that specimen (i.e. measurements, photographs, chromosome counts, scanning electron micrographs) could be related back to the specimen. Initial examination involved measurements (size, number) directly from the specimen (e.g. number of branchlets, number of branchlet segments) and with the use of a microscope (e.g. axis and branchlet diameter, number and morphology of stipulodes and bract cells, arrangement of gametangia). Oospore features were examined and measured with the aid of light microscopy and scanning electron microscopy.

Fresh specimens were obtained in field surveys in all states of Australia (following the methods of Casanova 2004), and from culture of seed-bank material in a greenhouse (following the methods of Casanova 2004). In the greenhouse, plastic containers (185 mm × 125 mm × 50 mm) containing ~300 g of wetland soil were inundated to a depth of 10–14 cm in large tanks and the charophytes that germinated from them were examined. When oospores were present they were removed from the specimens for examination with a scanning electron microscope (SEM), then plants were gathered and pressed, or preserved in 70% alcohol. If oospores were not present, the plants were either returned to culture to mature, or kept in jars on a windowsill until they matured and oospores were freely released. If antheridia were present, chromosome counts were attempted, following the methods outlined in Casanova (1997).

Where possible and appropriate, oospores were removed from the herbarium specimens or obtained as above from live material. Approximately a quarter (50) of the specimens examined had oospores. They were prepared for SEM examination by cleaning (if required) with a detergent solution, using a modification of the methods of Crawford et al. (2001). Sometimes the enveloping cells were removed by hand, using fine needles. For type specimens, very old material, or specimens with a single oospore available for examination, the oospores were handled with great care, with minimal manipulation. Oospores were removed from the stubs after microscopy and are stored in alcohol and deposited with the specimen for possible future examination.

Type: Chara vulgaris L.

Type: Chara braunii C.C.Gmel.

Monoecious or dioecious. Plant axis corticated or ecorticate, stipulodes in a single whorl (haplostephanous), bract cells unilateral or verticillate, branchlets ecorticate and terminated by a single cell, a cluster of bract cells or a group of three equal-sized cells (corona).

Protochara Womersley & Ophel, Trans. Roy. Soc. S. Australia 71: 311 (1947).

Chara sect. Monosiphoniae Wallr., Fl. crypt. Germ.2 107 (1833), p.p.; Chara hypogynae a. Monosiphoniae A.Braun, Ann. Sci. Nat. ser. 2, 1: 353 (1834) p.p. (excluding C. braunii); Chara sect. Charopsis (Kütz.) R.D.Wood, Taxon 11: 12 (1962), p.p. (excluding C. braunii).

Type: Chara protocharoides Casanova & Karol.

Axes ecorticate. Stipulodes in a single tier when present, sometimes obscure, up to 2 per branchlet. Branchlets ecorticate, with a single-celled end segment, sometimes surrounded by smaller bract cells. Bract cells 2 or 3, often obscure. Bracteoles 2, often replaced by gametangia or obscure. Gametangia sessile; solitary, geminate or aggregate, on the branchlet nodes and at the base of the branchlets, conjoined (monoecious) or on separate plants (dioecious). Oogonia with few circumvolutions, coronula cells slightly apiculate. Oospores with fewer than 8 striae, without a gyrogonite. Annual or perennial.

Species in this section have been variously placed in Chara, Nitella, Nitellopsis, Protochara and Tolypellopsis by previous authors. All these names refer to currently recognised genera, except Protochara and Tolypellopsis (=Nitellopsis). Thus, the name Protochara appears to be an appropriate name for the new section.

(Fig. 1)

Fig. 1.  Chara australis R.Br. A. Habit of whole plant; scale bar: 1 cm. B. Fertile antheridial whorl; scale bar: 10 mm. C. Fertile oogonial whorl; scale bar: 10 mm. D. Base of fertile oogonial whorl; scale bar: 1 mm. E. Branchlet node; scale bar: 0.5 mm. F. Base of sterile whorl; scale bar: 0.5 mm. G. Geminate oogonia; scale bar: 0.5 mm. H. Base of sterile whorl; scale bar: 1 mm. I. Fertile oogonial node; scale bar: 0.5 mm. J. Oospore; scale bar: 200 µm. K. Detail of smooth oospore wall; scale bar: 2 µm. L. Chromosomes n = 14, ×1000 magnification. A–C and J from M.T.Casanova r186; D, E from M.T.Casanova r612; F, G from D.McNeil r692; H, I from M.T.Casanova r952 and K, L from M.T.Casanova p788.

Nitella australis (R.Br.) Kütz. Tab. phycol. 7: 11 (1857)

Type: NEW SOUTH WALES: Port Jackson, 1804, R.Brown 277. Holo: BM; iso: LD.

Chara australis var. nobilis A.Braun in C.F.O.Nordstedt, Abh. Königl. Akad. Wiss. Berlin 1882: 105 (1883); Chara corallina var. nobilis R.D.Wood, nom. inval., Taxon 11: 12 (1962); Chara corallina f. nobilis R.D.Wood, nom. inval., Taxon 11: 12 (1962); Chara corallina var. nobilis (A.Braun) R.D.Wood, Rev. Characeae 1: 274 (1965); Chara corallina f. nobilis (A.Braun) R.D.Wood, Rev. Characeae 1: 274 (1965).

Type: NEW ZEALAND: Whangape [Whangapa?] Lake, T.K[irk] s.n., v.-1870, Lecto: NY (fide Wood and Imahori (1965: 275)); ?isolecto: WELT A9062 n.v., CHR n.v.

Dioecious. Plants robust, translucent and turgid, up to 40 cm high. Axes 0.9–1.75 mm wide, totally ecorticate, internodes 30–100 mm long. No spine cells. Stipulodes in a single row when present, 6–12 in a whorl, up to 0.38 mm long, but often absent or obscure. Branchlets almost uniformly 6 in a whorl, rarely 7, completely ecorticate, 3–5 cells long, cylindrical, 15–43 mm long, basal branchlet cell elongate, up to 15 mm long, branchlet end segments usually a single mucronate cell, sometimes with up to two subtending bract cells, bract cells 2–4 at a node, up to 0.2 mm long, frequently obscure or absent. Branchlets are often strongly incurved at the apices, especially in shallow water. Bracteoles obscure, possibly 2 per oogonium. Gametangia solitary, geminate or aggregate at the lowest 1 or 2 branchlet nodes and inside the base of the whorl, rarely antheridia sessile outside the base of the whorl. Oogonia orange, up to 1 mm long, 0.8 mm wide, coronula cells obtuse to slightly apiculate and usually very small on mature oogonia. Oospores black, cylindrical to ovate, 700–800 µm long, 450–600 µm wide, with 5 or 6 striae, appearing smooth or finely granulate, impression of the basal cell 180–200 µm in diameter. Antheridia up to 800 µm in diameter, orange and often very obvious. Vegetative reproduction by perennial basal internodes and the deposition of starch in the lower and rhizoid nodes. Chromosomes n = 14 (M.T.Casanova p426, p788).

Chara australis is the most common totally ecorticate species of Chara in eastern mainland Australia. It can be distinguished as dioecious, robust, ecorticate plants with large gametangia and small, often inconspicuous, stipulodes, bract cells and bracteoles. The internodes are usually as long as or longer than the branchlets and the axes are usually greater than 1 mm in diameter.

Occurring in cool, deep, still or slow-flowing water from east of Brisbane in Queensland, south through New South Wales (including the Australian Capital Territory) to Victoria, with an isolated collection from the Flinders Ranges in South Australia. Also occurs in New Zealand.

From the Latin ‘australis’, referring to the southern distribution of the species.

SOUTH AUSTRALIA: Mawson Plateau, Flinders Ranges, 20 May 2010, D.McNeil r692 (MEL). NEW SOUTH WALES: Dumaresq Creek above Dumaresq Dam near Armidale, 13 May 1990, M.T.Casanova p306 (MEL), p463 (NE), r396 (MEL); Dumaresq Creek below the dam near Armidale, 13 May 1990, M.T.Casanova p307 (MEL); Llangothlin Lagoon, seed-bank culture, 31 July 1992, M.T.Casanova p426, r977 (MEL); Beardy Waters, outside Glen Innes, M.T.Casanova, M.Feist & A. García r395 (MEL, NE); Little Manning River, between Gloucester and Walcha, 31 Oct. 1996, M.T.Casanova r397 (MEL); Deua River (Moruya River) Araluen Road, 9 Jan. 2009, M.T.Casanova r510, r514 (BM, MEL, NY); Tuross River on Comerang Road, Silo Farm Bridge, 10 Jan. 2009, M.T.Casanova r523 (BM, MEL, NY); Tuross River at Eurobodalla, Tyrone Bridge on Nerrigundah Road, 10 Jan. 2009, M.T.Casanova r528 (MEL); Dumaresq Dam, 17 Feb. 1988, M.T.Casanova r996 (MEL); Gledwood, Camden, cultured in biophysics laboratory, University of Sydey, 5 Dec. 1960, R.D.Wood 60-12-5-1 (AD, PC); Duval Creek, near Armidale, 17 Nov. 1960, R.D.Wood 60-11-17-14A and 15A (AD). AUSTRALIAN CAPITAL TERRITORY: Paddys River, 5 Apr. 1964, N.Burbidge 7428 (CANB); Point Hutt, Murrumbidgee River, 8. Jan. 1966, E.D’Arnay 466 (CANB, MEL); Murrumbidgee River, Uriarra, 4 Apr. 1964, H.S.McKee 11431 (CANB). VICTORIA.: Fitzroy River bridge, Tyrrendarra, A.C.Beauglehole 203 (MEL); Mount Emu Creek, Panmure Waterhole, 3 Mar. 2004, M.T.Casanova & R.L.A.Casanova p587 (MEL, NY); Lake Fyans, 24 Oct. 2005, M.T.Casanova p788 (MEL); Woorndoo Olympic Wetland, 24 Feb. 2008, M.T.Casanova r058 (MEL); Darlots Creek, Tyrendarra Bridge at the Budj Bim IPA, 29 Mar. 2011, M.T.Casanova r952 (MEL, NY); The Woolwash, Surry River, 2.5 miles SE of Heathmere, 31 Mar. 1962, A.Fuhrer & A.C.Beauglehole 181 (MEL, NY); Snowy River upstream of Sandy Creek confluence, 24 Jan. 1994, N.G.Walsh 2417 (MEL); Wonga Park, Warrandyte State Park, 3 Apr. 1994, D.J.van Bockel 384 & P.Coupar (MEL). NEW ZEALAND: Lake Oahu, Canterbury, South Island, 3 Mar. 2001, J.S.Clayton r402 (MEL).

(Fig. 2)

Fig. 2.  Chara corallina Klein ex Willd. A. Habit of whole plant; scale bar: 1 cm, after Kützing (1857). B. Upper branchlet whorl; scale bar: 1 mm. C. Lower branchlet whorl, two branchlets cut short; scale bar: 1 mm. D. Oogonium and branchlet node with bract cells; scale bar: 1 mm. E. Oospore; scale bar: 200 µm. F. Detail of oospore wall; scale bar: 20 µm.; G. Basal-cell impression, atypically six-sided; scale bar: 50 µm. A–C from J.G.Klein 510; E, F from G.O.Allen 104 and G from Lu & Soulié-Märshe 1996.

Nitella corallina (Klein ex Willd.) C.Agardh, Syst. alg. 123 (1824).

Type: INDIA: Wöppanpasi, Tranquebar (Tharamgambadi), near Madras (Chennai), Tamil Nadu, 7 Jan. 1799, Klein 510. Holo: B-W 17105; iso: MEL 2315415 & 2367911.

Monoecious. Plants usually elongate with stout branchlets, up to 40 cm tall, sometimes lightly encrusted with calcium carbonate. Axes up to 1.5 mm in diameter (~2 mm in flattened, preserved specimens), ecorticate, internodes up to 30 mm long, as long as or longer than the branchlets. Stipulodes crowded out by gametangia, 1 per branchlet, up to 380 µm long, often difficult to discern on pressed specimens. Branchlets 6 or 7 in a whorl, 20–60 mm long, somewhat pinched-in at the nodes, and appearing quite wide on pressed material, ecorticate, 4 or 5 cells long, branchlet end segment pointed, conical and acute, basal branchlet cell long, in diameter similar to the other branchlet cells. Bract cells small, 2–4 per branchlet node, 200–600 µm long, bracteoles difficult to distinguish, 2, similar to bract cells. Gametangia conjoined, clustered inside and below the branchlet whorls, and solitary or geminate on the lowest two branchlet nodes. Oogonia 0.8–1.0 mm long, 0.6–0.8 mm wide, coronula cells appressed, slightly apiculate. Oospores black, cylindrical, 600–830 µm long (778 ± 5 µm: Mandal et al. 2008) and 450–600 µm wide, 6 or 7 striae of low ridges, sometimes slightly flanged, the impression of the basal cell 165–180 µm in diameter. In a population from China (Lu & Soulié-Märshe, 1996), a proportion of the oospores had a 6-sided basal-cell impression, rather than a pentagonal basal-cell impression. Antheridia below or adjacent to the oogonia where they are at the same node, 500–750 µm in diameter. The antheridia appear tetrascutate. Chromosomes n = 42 (Khatun et al. 2009).

Living material of Chara corallina was not available for examination and the above description is based on the type material, the protologue, Nordstedt (1883), Imahori (1954) and the description of Indian material by Wood and Imahori (1964, icon 111). The status of C. corallina var. basilaris A.Braun, with gametangia absent from the branchlets and restricted to the base of the whorls, and C. corallina var. kyusyensis Imahori characterised by an almost complete absence of bract cells and stipulodes, cannot be commented on without reference to fresh specimens. The holotype material of C. corallina is lodged in the Willdenow collection in B, but oospores were not available for examination, apparently having been removed (R. Jahn, pers. comm.). Examination of material in the Sonder Herbarium at MEL revealed two specimens with morphology identical to the type material in B-W. One appears to have been used as the model for Kützing’s (1857) tabulae 80. These have been identified as isotypes of C. corallina, and the material is in good condition compared with the material in B-W (which appears to have been moistened, dissected and re-pressed).

Chara corallina is the only monoecious member of Chara sect. Protochara.

Chara corallina is apparently widespread in Asia, occurring in India, Bangladesh, Malaysia, Japan and China, at least as far north as Nanjing.

The term ‘corallina’ is derived from Latin corallinus meaning ‘coral-red’, referring to the bright colour of the gametangia.

INDIA: near Bombay, G.O.Allen 105 (BM). CHINA: Chengdu City, Sichuan, 1996, Lu Hui-nan & I.Soulié-Märsche s.n.,(NY, MEL: oospores only).

(Fig. 3)

Fig. 3.  Chara lucida (A.Braun) Casanova & Karol. A. Habit of whole plant; scale bar: 5 mm. B. Fertile oogonial branchlet whorl; scale bar: 5 mm. C. Final two branchlet cells; scale bar: 0.5 mm. D. Oogonium; 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 basal cell on the oospore; scale bar: 100 µm. A–D from M.T.Casanova r784; E from L.A.Craven 4782 and F–H from F.Mueller 5.

Chara australis var. lucida A.Braun in Nordst., Abh. Königl. Akad. Wiss. Berlin 1882: 106 (1883); Chara australis var. lucida f. typica Zaneveld, nom. inval., Blumea 4: 126 (1940); Chara corallina f. lucida R.D.Wood, nom. inval., Taxon 11: 13 (1962); Chara corallina f. lucida R.D.Wood, nom. inval., nom. alt., Rev. Characeae 1: 275 (1965); Chara lucida R.D.Wood, nom. inval., nom. alt., Rev. Characeae 1: 769 (1965).

Type: Northern Territory: Victoria River, s. dat., F.Mueller 5. Lecto (fide Zaneveld 1940): LD; isolecto: L. Syn: Northern Territory: Baines Creek, 1856, F.Mueller s.n.: LD.

Chara australis f. tenerior Zaneveld, Blumea 4 : 127 (1940).

Type: Gulf of Carpentaria, 1856, F.Mueller s.n. Holo: B (destroyed; fide Wood and Imahori (1965: 276)); iso: LD, L.

Dioecious. Plants flexible, transparent, often in tangled clumps, up to 200 mm tall. 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. 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, branchlet end segments small, conical and acute, sometimes subtended by 1 or 2 bract cells, bract cells obscure or short. 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. Oogonia 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, ornamentation smooth to minutely granulate, basal-cell impression 120–150 µm in diameter at the widest part, edges 95–100 µm long. Antheridia from 400–850 µm in diameter. Vegetative reproduction not known. Chromosomes not known.

Wood’s (1962) combination Chara corallina f. lucida is here treated as invalid, under Art. 41.5 of the ICN (McNeill et al. 2012). Wood and Imahori (1965) subsequently simultaneously published C. corallina f. lucida and C. lucida, the latter at the rank of ‘microspecies’, equivalent in rank to Wood’s forms as well as his ‘monotypic’ varieties and species (i.e. those lacking subordinate taxa). Both these names are here treated as invalid alternative names, under Art. 36.2 of the ICN (McNeill et al. 2012).

Zaneveld (1940) distinguished the following two formae in his concept of C. australis var. lucida, on the basis of material from New Guinea and northern Australia: f. typica, with somewhat stout (~600 µm wide), long branchlets, and f. tenerior, with shorter, narrower (~350 µm wide) branchlets. New collections from the Northern Territory (M.T.Casanova r784, r758) represent material with both long and short branchlets on apical parts of the same plant, and branchlet width varies in relation to branchlet length. Additionally, specimens from the Northern Territory and the Gulf of Carpentaria have identical oospores, and accordingly, no infraspecific taxa are here recognised in this species.

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. C. lucida forms tangled masses in warm waters, compared to the upright, turgid stems of C. australis in colder, deeper waters.

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

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 (fide Nordstedt 1883) of the pressed type material.

WESTERN AUSTRALIA: Rudall River, 29 May 2004, M.N.Lyons & D.A.Mickle 3057 (PERTH); Redrocks Granites, Pilbara Biological Survey site 080, 25 Aug. 2005, N.M.Lyons & D.A.Mickle 3160 (PERTH); Kumina Creek, Hamersley Ranges, 13 Aug. 1991, M.Trudgen & D.True MET10264 (CANB, AD, PERTH). NORTHERN TERRITORY: Manton Dam recreation area, 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);. QUEENSLAND: Ross River Dam overflow near Townsville, 12 May 1987, M.T.Casanova r997; in lagoon at Magoura Station, 18 July 1977, L.A.Craven, 4782 (CANB); Pig Swamp near Biboohra, N of Mareeba, 27 June 1962, R.D.Hoogland 8492 (CANB); Hastie Swamp, Atherton Tablelands, 6 Aug. 1970, A.P.Kershaw 10109 (CANB); Breeza Plains, 12 Aug. 1978, K.Paijmans 2871 (CANB); Enoggera Reservoir, 21 Nov. 1960, R.D.Wood 60-11-21-25 (AD, NY); Palm Creek at Miriam Vale, 30 Nov. 1960, R.D.Wood 60–11–30–6 (AD, NY); South Pine River, Bunya, 22 Nov. 1960, R.D.Wood 60-11-22-20 (AD, NY). PAPUA NEW GUINEA: Hisin Village, Kairuku, Central District, 16 Aug. 1962, P.J.Darbyshire 813 (CANB); Laloki River, Central District, 5 Sep. 1962, T.G.Hartley 10619 (CANB); Rouna Falls, Laoki River, Central District, 7 Sep. 1962, R.Schodde 2946 (CANB).

(Fig. 4)

Fig. 4.  Chara porteri Casanova. A. Habit of whole plant; scale bar: 1 cm. B. Branchlet whorl from an oogonial plant; scale bar: 5 mm. C. Individual oogonial branchlet; scale bar: 1 mm. D. Antheridial branchlet whorl; scale bar: 1 mm. E. Individual antheridial branchlet; scale bar: 1 mm. F. Oogonium; scale bar: 500 µm. G. Axis and branchlet whorl, with a bicellulate axis; scale bar: 1 mm. H. Oogonial axis tip, with clustered oogonia at the base of the branchlets; scale bar: 1 mm. I. Oospore; scale bar: 100 µm. J. Atypical six-sided basal-cell impression; scale bar: 50 µm. K. Oospore; scale bar: 100 µm. A from M.N.Lyons & D.A.Mickle 3061; B–F, I–J from M.N.Lyons & D.A.Mickle 3045 and G–H and K from M.N.Lyons & D.A.Mickle 3077.

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 in-curved branchlets in shallow water. 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. Stipulodes in a single row when present, frequently obscure or absent. 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, branchlet end segments small, conical and acute, occasionally subtended by bract cells, 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. Oogonia 0.6–0.75 mm long, 0.5 mm wide, coronula cells short, somewhat spreading, slightly apiculate. Oospores black, cylindrical, 470–525 µm long, 250–350 µm wide, 5 or 6 striae of wide ridges (pachygyra), ornamentation smooth to minutely granulate, basal-cell impression 100–120 µm in diameter at the widest part, edges 70–76 µm long, rarely 6-sided. Antheridia octoscutate up to 850 µm in diameter. Vegetative reproduction not known. Chromosomes n = 14 (M.T.Casanova r416).

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

Occurs in temporary wetlands (claypans and riparian overflows) in the Paroo region of New South Wales, the Pilbara region of Western Australia and in south-western Queensland.

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

WESTERN AUSTRALIA: Coondiner Pool, Pilbara Biological Survey site 001, 15 Aug. 2006, M.T.Casanova r416 and r417 (B, BM, MEL); Cooliarin Pool, M.N.Lyons & D.A.Mickle 3061 (paratype) (CANB, MEL, PERTH); Myanore Creek Pool, Pilbara Biological Survey site 014, 13 May 2006, D.A.Mickle & N.Y.Huang 3108, 3109 and 29-3108 (BM, MEL, PERTH); Watrara Creek Pool, Pilbara Biological Survey site 028, 8 Sep. 2003, M.N.Lyons & S.D.Lyons 3045 (PERTH); Cooliarin Pool, Pilbara Biological Survey site 033, 18 May 2004, M.N.Lyons & D.A.Mickle, 3064 (CANB, MEL, PERTH); Cooliarin Pool, Pilbara Biological Survey site 033, 20 Apr. 2006, M.N.Lyons & D.A.Mickle 3087 (AD); Cooliarin Pool, Pilbara Biological Survey site 033, 20 Apr. 2006, M.N.Lyons & D.A.Mickle 3089, 3090 and 13-3092 (PERTH); Sweetwell Claypan, Pilbara Biological Survey site 038, 21 May 2004, M.N.Lyons & D.A.Mickle 3069 (PERTH); Ethel Creek Claypan, Pilbara Biological Survey site 041, 1 June 2004, M.N.Lyons & D.A.Mickle 3074 (NY, BM); Redrocks Granites, Pilbara Biological Survey site 080 T1, 25 Aug. 2005, M.N. Lyons & D.A. Mickle 3159 (PERTH). QUEENSLAND: Cravens Peak site 4, Little Kanamuka, 17 Apr. 2007, I.J.Powling r399 (MEL). NEW SOUTH WALES: Pied Stilt Swamp, 27 Jan. 2000, J.L.Porter 239 & 240 (MEL).

(Fig. 5)

Fig. 5.  Chara protocharoides Casanova & Karol. A. Habit of plant; scale bar: 1 cm. B. Whorl of antheridial branchlets; scale bar: 1 mm. C. Branchlet tip with 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. Oospore; scale bar: 200 µm. G. Detail of oospore wall; scale bar: 20 µm. H. Impression of end cell; scale bar: 100 µm. A–D, F–H from H.B.S.Womersley 28-Aug-1947; E from M.T.Casanova r812.

Protochara australis Womersley & Ophel, Proc Roy. Soc. S. Australia 71: 311 (1947); Chara australis subsp. estipulodica M.B.Macdon. & Hotchk., Proc. Linn. Soc. New South Wales 80: 282 (1956) (non Chara australis R.Br., Prodr. 346 (1810)).

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

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 A5917a; Iso: AD A5917c, NY 01089127.

Dioecious. Plants up to 40 cm high, somewhat branched, variably inflated. Axes ecorticate, internodes 10–100 mm long, 0.9–1.5 mm in diameter in life (up to 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, elongate and cylindrical in deep-water populations, 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, 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 oogonia inside the base of the branchlet whorl. Oogonia 670–900 µm long × 600–780 µm wide with 6 or 7 convolutions, 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, sometimes flanged, and impression of the basal cell 80 µm in diameter. Antheridia 800–1150 µm in diameter, octoscutate. Vegetative reproduction not known; appears to be an annual in temporary water bodies. Chromosomes not known.

Originally placed in the segregate genus Protochara on the basis of very simple, inflated axes and the lack of accessory cells (bract cells, stipulodes or bracteoles) (Womersley and Ophel 1947). Apart from the absence of any accessory cells, type material of Protochara australis is otherwise consistent with the morphology of the genus Chara. The epithet australis is preoccupied in Chara (C. australis R.Br., 1810), and a new name is required for this taxon.

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

Grows in permanent, seasonal and temporary water bodies in Western Australia.

From the Latin ‘protocharoides’ in reference to the genus Protochara for which this species remains the type.

WESTERN AUSTRALIA: Bluegum Lake, Brentwood, Perth, 3 Oct. 2002, M.T.Casanova r392 (MEL); Swan Lake, Bayswater, Perth, 3 Oct. 2010, M.T.Casanova r805 (B, BM, MEL, NY, PERTH); small lake near inflow of Lake Leschenaultia, 5 Oct. 2010, M.T.Casanova r812 (MEL, NY, PERTH); River pool 2 km NNW of Tindellara Well, 20 Sep. 1987, R.J.Cranfield 6246 (PERTH); Hammersley River, in freshwater holes, 12 Oct. 1901, F.L.E.Diels 4913 (B); interior of western Australia, 1890, M.Heal (LD, MEL); Cape Bertholet, Dampierland, N of Broome, 18 Apr. 1977, K.F.Kenneally 6009 (PERTH); Yaladinia Rock Hole, 18 Sep. 1980, K.R.Newbey 7462A (PERTH); pool in woods, immediately S of Piesseville, 11 Oct. 1960, R.D.Wood 60-10-11-9a (AD); roadside pool, 3 miles (~4.83 km) S of Gnowangerup Road intersection, Tambellup, 10 Oct. 1960, R.D.Wood 60-10-10-11A (AD, CANB, PC).

(Fig. 6)

Fig. 6.  Chara stuartiana (F.Muell. ex Kütz.) Casanova & Karol, from specimen from the type locality, H. & A.Wapstra HAW044. A. Habit of whole plant; scale bar: 5 cm. B. Base of a branchlet whorl; scale bar: 200 µm. C. Two branchlet nodes; scale bar: 1 mm. D. Oogonium and end cells of branchlet; scale bar: 1 mm. E. Sterile branchlet whorl; scale bar: 1 cm. F. Branchlet end cells; scale bar: 0.5 mm. G. Scanning electron micrograph (SEM) of oospore; scale bar: 200 µm. H. SEM of detail of oospore wall; scale bar: 50 µm. I. SEM of impression of the basal cell; scale bar: 100 µm.

Nitella stuartiana F.Muell. ex Kütz., Tab. phycol. 7: 28 (1857); Chara stuartiana A.Braun, Linnaea 25: 707 (1853), nom. inval., pro syn.; Chara australis f. stuartiana (F.Muell. ex Kütz.) Zaneveld, Blumea 4: 126 (1940); Chara corallina f. stuartiana R.D.Wood, nom. inval., Taxon, 11: 13 (1962); Chara corallina f. stuartiana R.D.Wood, nom. inval., nom. alt., Rev. Characeae 1: 275 (1965); Chara stuartiana R.D.Wood, nom. inval., nom. alt., Rev. Characeae 1: 769 (1965).

Type: Tasmania: South Esk River, R.C.Gunn 1565, 1852. Holo: L; iso: PC.

[Chara australis var. nobilis auct. non A.Braun in C.F.O.Nordstedt, Abh. Königl. Akad. Wiss. Berlin 1882: 105 (1883).]

Dioecious. Plants large and inflated, transparent and turgid, up to 27 cm high, but fragile, fragmenting easily when handled. Axes 1.5–2.8 mm wide, ecorticate, internodes 30–120 mm long. Stipulodes in a single row, tiny, up to 12 per whorl, up to 400 µm long, alternate to the branchlets and pointing upwards. Branchlets 6 in a whorl, 20–30 mm long, 1.6–2.8 mm wide, 3 or 4 cells long, all cells cylindrical, end segment a single cell, or subtended by small bract cells, basal branchlet cell elongate and cylindrical, the second branchlet cell is usually shorter than the basal branchlet cell, abbreviated and sometimes almost spherical, particularly on the upper parts of the axis; bract cells 2 or 3 at branchlet nodes, up to 400 µm long. Bracteoles 2, up to 200 µm long. Gametangia on separate plants, solitary or geminate at all branchlet nodes. Oogonia at the lowest branchlet node, up to 1 mm long and 700 µm wide, with 8 convolutions, coronula very small and minutely apiculate. Oospores black, cylindrical to ovate, 615–700 µm long, 450–550 µm wide, with 6 or 7 striae of low ridges, basal-cell impression up to 140 µm in diameter at widest point, edges 85–115 µm long. Antheridia up to 500 µm in diameter, solitary, geminate or aggregate at the lowest branchlet node and inside the base of the whorl. Vegetative reproduction by starch accumulations in the lower and rhizoidal nodes. Chromosomes not known.

Wood’s (1962) combination Chara corallina f. stuartiana is here treated as invalid, under Art. 41.5 of the ICN (McNeill et al. 2012). Wood and Imahori (1965) subsequently simultaneously published C. corallina f. stuartiana and C. stuartiana, the latter at the rank of ‘microspecies’, equivalent in rank to Wood’s forms as well as his ‘monotypic’ varieties and species (i.e. those lacking subordinate taxa). Both these names are here treated as invalid alternative names, under Art. 36.2 of the ICN (McNeill et al. 2012).

Braun (1852) included a specimen collected by C. Stuart in Tasmania (Stuart 1565) in Chara australis. Kützing (1857) named the species Nitella stuartiana based on Stuart 1565 and provided an illustration (t. 28). Braun (1860) listed a collection from Tasmania, Gunn 1565, in his concept of C. australis. This is likely to refer to the same specimen as cited by Braun (1852) and Kützing (1857), and was collected by Gunn rather than Stuart, because the specimens attributed to Gunn have collection numbers for charophytes in the vicinity of Launceston (and the South Esk River) in the 1560s, and Stuart’s collection numbers for the South Esk River are either very low (3, 4, 5), in the 210s or in the 1020s. Only two specimens in sect. Protochara collected from Tasmania in the 1800s are known, including material used by Kützing for his illustration, almost certainly obtained from Sonder’s herbarium (L), and a specimen labelled ‘Nitella australis R.Br. Donné par Sir William Hooker, 1863; Ex Herb. Hook. Chara australis Br, Tasmania, Coll. R.C.Gunn’ (PC). It is possible that these are parts of the same gathering, and therefore the PC specimen would constitute isotype material. Braun, in Nordstedt (1883), retained N. stuartiana in synonymy of C. australis, but cited another specimen from Tasmania (Oldfield 283 n.v.) as C. australis var. nobilis. Zaneveld (1940) treated N. stuartiana as a form of C. australis var. nobilis. Proctor (1999) found that specimens identified as C. australis and C. stuartiana could be crossed to produce oospores, and explained C. stuartiana as a ‘genetically fixed morphotype of C. australis’. Examination of the type material and more recent collections indicated that most of specimens from Tasmania in sect. Protochara can be clearly separated from C. australis on the basis of more robust axes and branchlets, complex axial and branchlet nodes, overall fragility and different oospores. C. stuartiana is rarely collected as a whole plant, because the heavy, turgid axes are fragile and tend to break as they are removed from the water. The species still occurs in what is presumed to be the type locality, namely, the first basin of Cataract Gorge in Launceston. Specimens collected from Kimberley Warm Springs (T.Dugdale & S.Talman 20, HO, MEL, NY; H. & A.Wapstra HAW002, MEL, HO) appear to be C. australis rather than C. stuartiana, but if so, that is the only occurrence of C. australis known from Tasmania.

Chara stuartiana has large, fragile, often inflated, ecorticate axes and branchlets, with orange antheridia and oogonia. It can be distinguished from C. australis by its wide axes and branchlets, and by the abbreviated penultimate cell on the upper branchlet whorls.

Grows in Tasmania in rivers and streams, at depth.

Named for Charles Stuart (1802–1877) who collected charophytes in Tasmania from 1842 to 1852, initially for R.C.Gunn, later for F. von Mueller (Orchard 1999).

TASMANIA: Apsley River at Coles Bay Road, 7 July 2008, H. & A.Wapstra HAW009 (HO, MEL); Prosser River, Paradise Gorge, 1 Oct. 2008, H. & A.Wapstra HAW027 (HO, MEL); South Esk River, Glen Esk Bridge, 21 Oct. 2008, H. & A.Wapstra HAW044 (B, HO, MEL, NY); South Esk River, 22 Oct. 2008, H. & A.Wapstra HAW048 (HO, MEL, NY); Meredith River at Swansea, 22 Apr. 2009, H. & A.Wapstra HAW133 (HO, MEL); Curries River reservoir, 14 Oct. 2008, M.Wapstra HAW034 (HO, MEL); farm dam, Bridport road between Yarrow Creek and Pipers River, 15 Oct. 2008, M.Wapstra HAW036 (HO, MEL, NY); first basin of Cataract Gorge, 20 Feb. 2013, M.Wapstra HAW145 (HO, MEL); Elizabeth River, Campbell Town, 19 Jan. 1961, R.D.Wood 61-1-19-3 (AD, NY, PC); stream 6 miles (~9.66 km) S of Sorrel, 1 Feb. 1961, R.D.Wood 61-2-1-2 (AD, NY, PC); 15 miles (~24.14 km) S of Seymour, 2 Feb. 1961, R.D.Wood 61-2-2-6 (AD, NY); St Pauls River, 3 Feb. 1961, R.D.Wood 61-2-3-6 (AD, NY); South Esk River, 3 Feb. 1961, R.D.Wood 61-2-3-7 (AD); 2 miles (~3.22 km) N of Longford, 4 Feb. 1961, R.D.Wood 61-2-4-14 (AD, NY).

(Fig. 7)

Fig. 7.  Chara wallichii A.Braun, from Parsotam 230. A. Habit of whole plant; scale bar: 1 cm. B. Branchlet tip; scale bar: 1 mm. C. Branchlet whorl from an antheridial plant; scale bar: 1 mm. D. Oospore; scale bar: 200 µm. E. Detail of oospore wall; scale bar: 20 µm.

Chara corallina var. wallichii R.D.Wood, nom. inval., Taxon 11: 13 (1962); Chara corallina var. wallichii (A.Braun) R.D.Wood, Rev. Characeae 1: 278 (1965), nom. inval., nom. alt.

Type: INDIA: Gangetic Plain, leg. ign., 9 Jan. 1809. Holo: LINN, n.v.

Dioecious. Plants up to 25 cm high, prickly in appearance. Axes ecorticate, 875–1100 µm wide, internodes somewhat shorter than the branchlets. Stipulodes well developed and somewhat inflated where present, up to 450 µm long. Branchlets 6 in a whorl, ecorticate, up to 30 mm long, 4–6 cells long, basal branchlet cell longest, the end segment short, conical and acute. Bract cells well developed, 1–4 at a node, up to 2 mm long. Gametangia on separate plants, clustered at the base of the whorl and singly or geminate at all branchlet nodes. Oogonia up to 745 µm long, 700 µm wide, with 7 or 8 convolutions. Oospores 500–610 µm long, 330–440 µm wide with 6 or 7 flanged ridges. Antheridia 750–950 µm in diameter, tetrascutate (Wood and Imahori 1965). Chromosomes not known.

Wood’s (1962) combination Chara corallina f. wallichii is here treated as invalid, under Art. 41.5 of the ICN (McNeill et al. 2012). Wood and Imahori (1965) subsequently simultaneously published C. corallina var. wallichii and C. wallichii, the latter at the rank of ‘microspecies’, equivalent in rank to Wood’s forms as well as his ‘monotypic’ varieties and species (i.e. those lacking subordinate taxa)). C. corallina var. wallichii is here treated as invalid, under Art. 36.2 of the ICN (McNeill et al. 2012).

Chara wallichii is a dioecious species that, in contrast to most other species in the group, is distinguished by well developed, somewhat inflated, stipulodes and bract cells. Material seen in BM and BP is relatively uniform.

India and Bangladesh.

Named in honour of Nathaniel Wallich (1786–1854), a Danish botanist involved in the development of the Calcutta Botanic Garden.

INDIA: Sarmalt, Benares, Uttar Pradesh, Jan. 1934, Parsotam 230, (BP, BM).

Known only from the type gathering from Lake Toba, a deep, oligotrophic caldera in Sumatra, in 1929. The morphology of this species is similar to that of C. australis; however, the oogonia are much smaller and more spherical than those of any other species in sect. Protochara. Because of its overwhelming morphological similarity to other species in sect. Protochara, it is likely to be a species of Chara. It does not appear to have many accessory cells (stipulodes, bract cells); however, further collections of mature female material is required for confirmation of the identity and placement of this taxon.

Known only from the type gathering from ‘Carpentaria Point’, possibly the ‘Carpentaria Main’ of Brown’s and Flinders’ diaries, now known as Cape Shield (Groves and Moore 1989), in Arnhem Land near Groote Eylandt in the Gulf of Carpentaria. Satellite images of the locality of Cape Shield revealed a hind-dune wetland area that could be where Brown collected this species. Treated as a subspecies of C. australis by Braun in Nordstedt (1883) and as a variety of C. australis by Zaneveld (1940), and distinguished from C. australis sens. str. on the basis of obtuse end cells on the branchlets. Detailed examination of the type material revealed a few stipulodes and bract cells, and what appear to be obtuse end cells are probably penultimate cells, with the end cells dehiscent. Given the possible habitat and evidence from the morphology (7 or 8 branchlets rather than 6, stipulodes opposite the branchlet and somewhat decumbent), it seems likely that C. plebeja is a species of Lamprothamnium. If so, it would be the only known coastal Lamprothamnium from the tropics. Further collections of fertile female material are required to confirm this.

This specimen is likely to represent a new species. Oospores are similar in appearance to those of C. porteri, but are over 700 μm long (c.f. C. porteri with oospores 470–525 µm long), and its distribution is disjunct from C. porteri. However, there are insufficient gatherings to confirm its status at the present time.

Several other species have been recorded from the Indian subcontinent (Chara fulgens Fil., C. pashanii S.C.Dixit and C. nuda Pal) and oceanic islands of the southern hemisphere (Chara socotrensis Nordst. from Socotra, C. corallina f. vieillardii (A.Braun) R.D.Wood from New Caledonia, C. corallina f. vitiensis Nordst. from Fiji and C. corallina f. mascarensis J.Groves & Stephens, nom. inval., nom. prov. from Mauritius); however, because specimens have not been examined, no comment on their status can be made in the present study.

Species in sect. Protochara have few characters to aid discrimination, a fact that has contributed to the confused history of generic and species names in this group. Axis and branchlet diameter and the expression of accessory cells (stipulodes, bract cells) can allow discrimination in well grown plants; however, the occurrence and expression of basal gametangia and abundance of branchlet gametangia probably vary in relation to plant nutrition and age and there are examples of specimens that fail to conform to the ‘average’ morphology (e.g. from cultured material, young plants growing in shallow water, or etiolated plants from deep water). Reference to the oospore morphology is necessary to distinguish such doubtful specimens.

Separation of Chara sect. Protochara and the genus Lamprothamnium (also ecorticate, sometimes inflated, sometimes with few accessories) on the basis of vegetative morphology will always be something of a challenge, particularly with material lacking diagnostic characters. These two taxa appear to be closely related on the basis of nucleotide-sequencing studies (Meiers et al. 1999; McCourt et al. 2000). The main characters to aid identification are that Lamprothamnium species usually have more than six branchlets in a whorl, their stipulodes are opposite and decumbent when present, and the oospores possess gyrogonites (a calcified covering). Additionally, most members of sect. Protochara occur in freshwater, whereas Lamprothamnium species occur in brackish to saline water.

Chara braunii (sect. Charopsis) can be separated from members of sect. Protochara phylogenetically (Meiers et al. 1999; McCourt et al. 2000) and morphologically. C. braunii has well developed stipulodes and bract cells, and the branchlets are terminated by a ‘corona’ of approximately three equal-sized cells, rather than a single cell, as in sect. Protochara. C. braunii is a relatively ephemeral charophyte, and is rarely found in Australia, with most specimens referred to C. braunii in Australian herbaria being referable to C. muelleri.