Nitella townsendii Casanova, 2023

Casanova, Michelle T. & Karol, Kenneth G., 2023, Charophytes of Australia’s Northern Territory - II. Tribe Nitelleae, Australian Systematic Botany 36 (4), pp. 322-353 : 348

publication ID

https://doi.org/ 10.1071/SB22029

DOI

https://doi.org/10.5281/zenodo.10904359

persistent identifier

https://treatment.plazi.org/id/A70387E4-9433-2759-7EF5-28AF4C2FFC52

treatment provided by

Felipe

scientific name

Nitella townsendii Casanova
status

sp. nov.

Nitella townsendii Casanova , sp. nov.

Type: Northern Territory: Parkin Rd, Livingston , 6 May 2010, P.Dostine 49DW73-4 (holo: DNA!) .

Monoecious. Plants up to 8 cm high, with mucus; apparently rhizomatous ( Fig. 15 a View Fig ). Axes 400 µm wide; internodes 10–20 mm long, often longer than the sterile branchlets. Fertile branchlets 6–8 in a whorl ( Fig. 15 e View Fig ); 2×furcate; primary segments to 1.5–4 mm long; secondary segments 4–7, some without gametangia up to 3 mm long; some much shorter (0.8 mm) and with gametangia; 2–4 tertiary segments 0.6–1 mm long. Sterile branchlets 6 in a whorl ( Fig. 15 d View Fig ); unevenly 2 or 3×furcate; primary segments up to 15 mm long; secondary segments 5–7, up to 6 mm long; tertiary segments 6–8, up to 8 mm long. Fertile and sterile dactyls similar, bicellulate; 0.5–0.8 μm long, tapering to a long, conical, acute end-cell ( Fig. 15 c, g View Fig ). Heads not formed; fertile branchlets somewhat contracted; mucus abundant around the gametangia ( Fig. 15 e View Fig ). Gametangia conjoined at the fertile branchlet nodes, but antheridia appear to dehisce before oogonia mature ( Fig. 15 b View Fig ). Oosporangia single or geminate ( Fig. 15 b, g View Fig ), up to 350 µm long; coronula up to 15 µm high, upper cells longer ( Fig. 15 f View Fig ). Oospores dark brown, 190–230 µm long × 180–190 µm wide with 7 or 8 striae ( Fig. 15 h View Fig ) with robust, figured, porate flanges ~5 μm high; ornamentation of ropy, sinuous vermiculae and verrucae ( Fig. 15 j View Fig ). End-cell impressions quite small ( Fig. 15 i View Fig ). Antheridia up to 150 µm in diameter ( Fig. 15 i View Fig ). Chromosome numbers not known.

Taxonomic notes

The oospores and other morphological characters of this species are most similar to Nitella vermiculata J.Groves from Madagascar; however, the diameter of the vermiculate elements on the oospore wall of N. vermiculata are much narrower, and N. townsendii has a more ropy and perforate flange.

Recognition

Nitella townsendii is monoecious and has bicellulate dactyls and viscous mucus around the gametangia. The dactyls are somewhat in-curved at their tips, and the branchlets have more than five segments at each furcation. The oospores are especially distinctive.

Distribution

Rivers and streams around Darwin.

Etymology

Named for Simon Townsend, who has collected charophytes in the Northern Territory.

Specimens examined

NORTHERN TERRITORY: Billabong next to the Darwin River 4 May 2011, J. Schult t841 ( MEL) .

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

J

University of the Witwatersrand

MEL

Museo Entomologico de Leon

Kingdom

Plantae

Phylum

Charophyta

Class

Charophyceae

Order

Charales

Family

Characeae

Genus

Nitella

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