Nitella belangeri (A.Braun) A.Braun, Monatsber. Königl. Preuss. Akad. Wiss.

Casanova, Michelle T. & Karol, Kenneth G., 2023, Charophytes of Australia’s Northern Territory - II. Tribe Nitelleae, Australian Systematic Botany 36 (4), pp. 322-353 : 326-328

Nitella belangeri (A.Braun) A.Braun, Monatsber. Königl. Preuss. Akad. Wiss. Berlin 1858: 353, 355 (1859)

Nitella acuminata var. belangeri A.Braun. Hookers J. Bot. Kew Gard. Misc. 1: 292 (1849), as ‘Bellangeri ’

Nitella acuminata β belangeri (A.Braun) Wallman, Actes Soc. Linn. Bordeaux sér. 3, 21: 30 (1856), as ‘ Bellangeri ’

Nitella acuminata f. belangeri (A.Braun) R.D. Wood , Nova Hedwigia 22: 41 (1971).

Type: in pools near Gengu, on the coast of Coromandel, 1826–28, Bélanger s.n. (holo: B n.v. [destroyed, fide R.D. Wood & K.Imahori, Revis. Charac. 1: 409 (1965)]; Bombay, Concan, 1847, J. L.Stockes s.n. (neo: BM 000904580!, here designated).

Monoecious. Plants not calcified, 10–15 cm high ( Fig. 2 a ), tangled and compact in shallow water. Axes up to 450 µm wide; internodes up to 6 mm long, as long as the sterile branchlets. Fertile branchlets homeoclemous (i.e. in a single whorl), 5 or 6 in a whorl, 1× furcate; primary segments up to 2 mm long; secondary segments 2 or 3, up to 4 mm long (usually dactyls) ( Fig. 2 d ); sterile branchlets homeoclemous, 6 in a whorl, 1× furcate; primary segments up to 5 cm long; secondary segments 1–3, up to 2.5 cm long ( Fig. 2 b ). Fertile and sterile dactyls similar, single-celled; between 1 and 5 mm long, tapering gradually to an acuminate tip ( Fig. 2 c, d ). Heads not formed, the fertile branchlets shorter and closer together than the sterile branchlets, without mucus. Gametangia conjoined at the fertile branchlet nodes ( Fig. 2 e ). Oosporangia solitary or geminate ( Fig. 2 e ); coronula up to 30 µm high, with equal-sized cells ( Fig. 2 f ). Oospores up to 280 µm long and 215 µm wide, with 7 flanged striae ( Fig. 2 g ), the flanges up to 30 µm high; ornamentation of scattered, flaccid dentate scales up to 2 µm high ( Fig. 2 h ); basal-cell impressions 65 µm wide at the widest part, the larger cell pentagonal, the smaller cell rectangular ( Fig. 2 i ). Antheridia up to 300 µm in diameter ( Fig. 2 e ). Chromosome numbers not known.

Taxonomic notes

The lectotype material of Nitella acuminata A.Braun (Commerson, s.d. ( LD!)), and other material from Indian Ocean Islands ( Réunion, Mauritius, Madagascar ( BM!, PC!)) was compared with specimens of N. acuminata from India, Indonesia, Philippines and Australia (particularly those mentioned by Braun in Nordstedt 1883 and by Zaneveld 1940). The Australian material has identical oospores and similar morphology to collections of the same taxon from India, whereas the material from Indian Ocean Islands (and other specimens included in N. acuminata from North America) has substantially different oospores (porate, or flocculate and with densely arranged flaccid conical elements). Eastern Asian specimens seen are similar to the Indian material.

In the absence of the holotype, the specimen ‘Concan, 1847, J. L.Stockes s.n. ’ ( BM 000904580) is designated as neotype of Nitella acuminata var. belangeri A.Braun. The specimen was collected from East India, conforms to the type description and was examined by Braun (in Nordstedt 1883, p. 38) and by Zaneveld (1940, p. 60), who both assigned the name N. acuminata var. belangeri to it. The variety is here recognised at species rank, pending further investigation.

Nomenclatural notes

Braun’s (1849, p. 292) first mention of this taxon was a Latin description of Nitella acuminata var. belangeri , with a separate diagnosis in English validating the species name N. acuminata given in notes on the following page. Zaneveld (1940, p. 60) stated that the holotype specimen (Coromandelia, in

pools near Gengu, 1826–28, Bélanger s.n.) was annotated by Braun, first as ‘ Nitella Bellangeri A. BR. 1838 ’, then as ‘ Nitella ( acuminata ) Belangeri 1858’. Nitella acuminata was cited with a Latin description by Wallman (1856), with a reference to Braun’s manuscript name Chara flexilis var. acuminata for a specimen from Réunion (Île Bourbon, legit Commerson ( LD)). A slightly modified Latin description for Nitella acuminata var. belangeri (as Nitella acuminata β belangeri (A.Braun) Wallm. ) was provided in that publication, with the Bélanger collection cited. Braun (1859) later referred to it at species level without further description.

Recognition

This is the only Nitella species in Australia with single-celled dactyls and a single whorl of branchlets at the axis nodes. The other species with single-celled dactyls in Australia, Nitella stuartii A.Braun , is distinguished by having more than one whorl of branchlets at the nodes, and it occurs in eastern Australia, north to central Queensland ( Casanova and Karol 2008). Nitella belangeri is distinguished from other species related to N. acuminata chiefly via the ornamentation on the oospore wall, and by the arrangement of gametangia.

Distribution

Nitella belangeri appears to be restricted to the north in Australia. It grows in shallow wetlands and temporary streams at the end of the wet season in northern Australia and eastern Asia, being fertile from June to September.

Etymology

Named for the collector of the original material, Charles Paulus Bélanger (1805–1881), a French explorer and naturalist working in Pondicherry between 1825 and 1829.

Specimens examined

WESTERN AUSTRALIA: Moochalabra Dam , 8 Aug. 1995, S. W. Jacobs s.n. ( MEL, NSW); Caliwingina Spring , M. Curran 2 ( MEL). NORTHERN TERRITORY: George Brown Darwin Botanic Garden, M. T. Casanova r737 (DNA, MEL, NY); floodplain billabong near Gunlom Campground, Kakadu National Park , J. Schult 11-vi-2012 ( MEL) [oospores only]. QUEENSLAND: Davies Creek , Mareeba, H. S. McKee 9372 ( CANB, MEL, NY); Edge Hill , 31 May 1936, H. Flecker 1707 ( BM, NY). INDONESIA: Java, Malang, Roemah, Kampok , 14 May 1936, JH 75 ( L). PHILIPPINES: Rangii , on swamp brook and open llocus norto, 40 cm ASL, 22 Feb. 1917, M. Ramos 27630 ( NY) .

Figures

Fig. 2. Nitella belangeri from the specimen M.T.Casanova r737 (MEL). (a) Habit of whole plant, scale: 5 cm. (b) Sterile branchlet whorl, scale: 5 mm. (c) Fertile branchlet whorl, scale: 1 mm. (d) Three fertile branchlets, scale: 1 mm. (e) Dactyls and gametangia, scale: 0.5 mm. (f) Oogonium, scale: 100 µm. (g) Scanning electron microscope (SEM) image of oospore, scale: 100 µm. (h) SEM image of detail of oospore wall, scale: 10 µm. (i) SEM image of view of basal-cell impressions, scale: 50 µm.