Chara globularis Thuill., Fl. Env. Paris

Casanova, Michelle T. & Karol, Kenneth G., 2023, Charophytes of Australia’s Northern Territory - I. Tribe Chareae, Australian Systematic Botany 36 (1), pp. 38-79 : 59-61

Chara globularis Thuill., Fl. Env. Paris 2nd edn, 472 (1799)

Type: loc? In the vicinity of Paris , s. dat., Thuillier s.n. (lecto: L 0054649 !, fide J.S.Zaneveld, Blumea 4: 191 (1940)) [annotated ‘ most probably co-type ’ by J.C.van Raam]; Hab. in Gallia , s. dat., [Thuillier?] (epi: PC 0074031 !, fide H.Sakayama et al., J. Phycol. 45: 926 (2009)) .

Monoecious. Plants up to 200 mm high, with light calcium carbonate deposition on the thallus. Axes narrow, 400–500 µm in diameter ( Fig. 12 a ); 3× corticated, evenly isostichous, ~21 cells around ( Fig. 12 d ). Spine cells absent or inconspicuous. Stipulodes inconspicuous, in two whorls, 2× the number of branchlets in each whorl, globular or rudimentary, clearly present on young nodes, sometimes obscure on old nodes ( Fig. 12 d ). Branchlets 7 or 8 in a whorl, 14–32 mm long, 5–8 segments, corticated with ~12 cortical cells around, terminated by a 2–4-celled uncorticated segment ( Fig. 12 c ). Bract cells obscure and globose, abaxially up to 500 μm long, bracteoles 2, beside gametangia, 100–500 μm long, 50–80 μm wide ( Fig. 12 b ). Gametangia conjoined at the lowest 2–5 branchlet nodes ( Fig. 12 e ). Oosporangia up to 1000 µm long and 400 µm wide, coronula up to 100 µm high, appressed. Oospores black, 600–700 µm long, 300–350 µm wide, usually with ‘basal claws’ and a ‘cage’, often with a thin calcified covering (gyrogonite 800 µm long). Striae of 11 or 12 ridges with a delicate ribbon (flaccid flange) ( Fig. 12 f ), fossa wall 40–50 μm across, minutely papillate ( Fig. 12 g ). Ribbon with nodular structures. Antheridia up to 450 µm in diameter. Chromosomes n = 42 for a Victorian specimen ( Fig. 12 h ) (Casanova 2015).

Distribution

One of the few apparently cosmopolitan species of charophytes, occurring on all continents except Antarctica. Occurs throughout Australia, in shallow, mostly permanent, sometimes turbid, sometimes slightly saline waterbodies. In the Northern Territory, it has been collected only in the arid zone in dams, bores and canyon waterholes.

Habitat and ecology

Chara globularis occurs in a diversity of habitats, from highly turbid to clear running water. It often grows in somewhat eutrophic and modified conditions (e.g. park ponds). It can be a perennial species, but usually reproduces sexually in its first year (Schubert et al., in press). Ripe oospores can be found from October to April in Australian material.

Etymology

Apparently named for the globular stipulodes, bract cells and spine cells.

Notes

Chara globularis has often been referred to as Chara fragilis Desv. [in Loisel., Not. Fl. France: 137. 1810] in the past. This name must be regarded illeg. because the description refers to ‘ Chara vulgaris Thuil. ’, which was used already for Chara vulgaris L. in Thuillier (1799, p. 471).

Wood (1962) amalgamated a large number of taxa into Chara globularis , sometimes retaining previously published species names at the varietal and form level . Proctor (1971) found that ‘ C. globularis ’ sensu Wood consisted of many reproductively isolated lineages. Sakayama et al. (2009) investigated the phylogeny of different Japanese specimens that keyed out to Wood’s Chara globularis f. globularis . They found that they could distinguish different genetic entities on the basis of branchlet morphology and oospore characters, describing C. leptospora Sakayama on the basis of the length of the end-segment of the branchlets (1 or 2 cells, up to 3.7 mm long) and elongate oospores with a granulate to papillate oospore wall and a rough nodular pattern on the ribbon structure (flange). The type material of C. globularis has shorter end-segments and broader oospores, with a fine pusticulate ornamentation and fine nodular elements on the ribbon ( Sakayama et al. 2009). Northern Territory material falls somewhere in between these, because the oospore ribbon is similar to that of the type material, but oospore shape is similar to that of C. leptospora and the branchlets have an elongate 2- or 3-celled end segment. The name C. globularis is retained for this material pending further investigation.

Chara globularis is smooth-looking and characterised by a distinct foetid or garlic smell when fresh. It is distinguished from C. setosa and C. zeylanica on the basis of its evenly corticated basal branchlet cell, inconspicuous spine cells, and globose stipulodes.

Specimens examined

NORTHERN TERRITORY: Trephina Gorge, East MacDonnell Ranges , 5 Aug. 1957, G. Chippendale s.n. (DNA, MEL); Wigleys waterhole, Alice Springs, Telegraph Station Reserve , 21 Apr. 2012, I. J. Powling v051 ( MEL); Alice Springs Primary Industries Research Farm turkey nest tank, 19 Aug. 1968, D. J. Nelson 1735 (DNA); Bottom Bore, Neutral Junction turkey nest, 25 May 1984, R. Dance 735 (DNA); 9 km ESE of Allambi Homestead , 5 Nov. 2001, P. K. Latz 18274 (DNA, NSW, NT); East Mann Range , 90 km W of Amata, 1 Sep. 2009, P. K. Latz 24732 ( AD, DNA, NT); No. 4 Bore , 23 km SSE Atula Homestead, 5 Nov. 2008, P. K. Latz 23905 (DNA, NSW, NT). WESTERN AUSTRALIA: Bibra Lake seed bank (cultured), 17 Jan. 2002, M. T. Casanova p473 ( MEL); Margaret River seed bank (cultured), 14 Nov. 2009, M. T. Casanova p801 ( MEL) .

Figures

Fig. 12. Chara globularis, (a, b) from specimen M.T.Casanova p473, (c–g) from the undated lectotype specimen Thuillier (L), (h) from specimen M.T.Casanova p801. (a) Habit of whole plant, scale bar: 1 cm. (b) Immature gametangia, scale bar: 1 mm. (c) Branchlet whorl, scale bar: 1 mm. (d) Base of branchlet whorl with globular stipulodes and globular spine cells, scale bar: 1 mm. (e) Mature gametangia, scale bar: 1 mm. (f) Scanning electron micrograph (SEM) of oospore, scale bar: 100 µm. (g) SEM of detail of oospore wall, scale bar: 20 µm. (h) Light micrograph of antheridial cells in metaphase, n = 42, 1000× magnification.