Nitella microcarpa A. Braun (1858: 357)

Borges, Fabio Renato & Jr, Orlando Necchi, 2018, Taxonomy and phylogeny of Nitella (Charophyceae, Characeae) from Brazil with emphasis on the midwest and southeast regions, Phytotaxa 356 (3), pp. 181-198 : 192-193

Nitella microcarpa A. Braun (1858: 357)

Figs. 29–34

Plants monoecious, up to 24 cm high, without calcium carbonate deposition.Axes 113–1035 μm in diameter, internodes 0.06–5.3 cm long, 0.16–3.2 (mean 0.8) times as long as the branchlets. Branchlets (4)5–6(–8) in a whorl, 0.24–5.00 cm long, (2)3–4(5) furcated; primaries rays (4)5–6(–8), 0.11–2.00 cm long, 190–795 μm in diameter; secondaries rays (2–)4–6, 0.07–1.2cm long, 76–601 μm in diameter, with or without central ray; tertiaries rays (2)3–4(–6), 0.05–1.55cm long, 52–483 μm in diameter, whit or without central ray; quaternaries 2–4, 0.08–0.8 cm long, 42–425 μm in diameter; quinaries rare. Dactyls (1)2–3(4), 2(3) celled, usually abbreviated, 0.007–0.25 cm long, 25–230 μm in diameter, penultimate cell rounded at distal end; end cell conical, acuminate, mucronate. Heads lacking. Gametangia sejoined or conjoined at all branchlets nodes, without mucus. Oogonia 1–4 at a node, 142–557 μm long (excl. nucula), 128–467 μm in wide; convolutions (4)5–7(8); coronula 30–93 μm high, 33–107 μm wide at base, upper cells normally higher than basal cells; coronular cells convergent, persistent. Oospores light to dark brown, 171–351 μm long, 160–306 μm wide; striae 5–7; fossa 35–80 μm across; membrane reticulate with papillae at the junctions under LM and beaded imperfect reticulate under SEM. Antheridia solitary, 112–244 μm in diameter, 8 scutate.

Specimen examined:— BRAZIL. Goiás: BR 070 , between the Municipalities of Aragarças and Jussara , elev. 307m, 15°53’38.4”S ; 51°39’56.9”W, 15 April 2015, coll. F. R. Borges ( SJRP32570 ). Mato Grosso: Entrance to São Nicolau Farm , Municipality of Cotriguaçu , 09°51’25.1’’S, 58°15’11.0’’W, 25 May 2011, coll. F. R. Borges ( SJRP32541 ). São Nicolau Farm , Municipality of Cotriguaçu , 09°49’21.5’’S 58°17’11.2’’W, 25 May 2011, coll. F. R. Borges ( SJRP32543 ). Lagoon located in Parque Florestal de Sinop , Municipality of Sinop , 11°50’02.83’’S, 55°30’00.98’’W, 2 June 2013, colls. F. R. Borges and O. Necchi Jr. ( SJRP32544 ). BR 070 , between the municipalities of Primavera do Leste and Barra do Garças , elev. 199m, 15°44’41.8”S, 53°47’8.6”W, 14 April 2015, coll. F. R. Borges ( SJRP32558 ). Mato Grosso do Sul: Entrance to the Recanto da Barra Farm , BR262 , near KM484 , between the municipalities of Terenos and Anastácio, 20°30’6.1’’S, 55°45’34.7’’W, 13 May 2014, coll. F. R. Borges ( SJRP32554 ). São Paulo: Piedade Stream, Municipality of São José do Rio Preto , elev. 507m, 20°52’30’’S, 49°22’35.7’’, 3 September 2014, colls. F. R. Borges and O. Necchi Jr. ( SJRP32532 ) .

DNA sequences: rbc L- MG010419, MG010418, MG010421, MG010420, MG010423, MG010422, MG010424; ITS1- MG029141, MG029140, MG029139, MG029138; ITS2- MG029141, MG029151, MG029140, MG029139, MG029138.

Figures

FIGURES 29–34. Nitella microcarpa. 29. Upper whorls somewhat compacted. 30. Dactyls 2-celled, abbreviated, forming a crown. Penultimate cell rounded at distal end. End cell conical and acuminate. 31. Fertile branchlet with gametangia at second (black arrow) and third (red arrow) nodes. 32. Oospore membrane with reticulate aspect under LM. 33. Overview of an oospore under SEM. 34. Oospore membrane with beaded imperfect reticulate aspect under SEM.