Chara rusbyana M. Howe 1929: 160–161

Borges, Fabio Renato & Jr, Orlando Necchi, 2017, Taxonomy and phylogeny of Chara (Charophyceae, Characeae) from Brazil with emphasis on the midwest and southeast regions, Phytotaxa 302 (2), pp. 101-121 : 113-115

Chara rusbyana M. Howe 1929: 160–161

Fig. 36–39

Plants up to 39 cm high, with strong calcium carbonate deposition. Axes 424–1123 μm in diameter; internodes 0.12–2 times longer than the branchlets, to 3.8 cm length; cortex 3 corticate, isostichous; spine-cells solitary, well developed, 87–435 μm long, 44–96 μm in diameter at base, concentrated at apical internodes. Stipulodes in two whorls, two times as numerous as the branchlets always exceeding basal branchlet segment; uppers 495–824 μm long, 63–123 μm in diameter, acuminate; lowers 190–535 μm long, 66–122 μm in diameter, acuminate. Branchlets 13–16(17) forming a whorl, 0.8–2.4 cm long; intercalary segments 6–11, corticate, 430–3000 μm long, 113–555 μm in diameter; basal segment ecorticate, 248–685 μm long, 198–477 μm in diameter; apical segment formed by 1 ecorticated cell, 417–713 μm long, 67–150 μm in diameter. Bract-cells (4)5–8, forming whorls, 107–348 μm long, 57–86 μm in diameter, acuminate. Oogonia and antheridia not observed.

Specimen examined:— BRAZIL. Mato Grosso do Sul: Anhumas Stream, road leading to the grotto Lagoa Azul, near the entrance of the São Miguel Cave , Municipality of Bonito , 21°06’07.8’’S ; 56°34’17’’W, 14 May 2014, coll. F. R. Borges ( SJRP28307 ). Seputá Stream, Municipality of Bonito, 21º03’51”S, 56º44’25”W, 14 Aug 2002, coll. L. H. Z. Branco. Olaria Stream, Municipality of Bonito , 20º55’02”S, 56º35’01”W, 15 Aug 2002, coll. L. H. Z. Branco .

The samples from Seputá and Olaria Streams had only few fragments and not enough to perform observations and measurements of the morphological characters. The ITS2 marker was not amplified for these samples.

DNA sequences:— rbc L-KY656909, KY630506, KY656905; ITS2-KY656929; mat K-KY656920, KY630507, KY656916.

FIGURES: 28–35. Chara hydropitys . 28. Habit. 29. Stipulodes (black arrows) in one tier, and branchlets with ecorticated basal segment. 30. Ecorticated basal segment of a branchlet and an antheridium (blue arrow) at the first node. 31. Apical segment with one ecorticated cell and bract-cells around. 32. Monoecious plant with conjoined gametangia (the red arrow indicates an oogonium and the blue an antheridium). 33. Granular aspect of the osospore wall under light microscope. 34. Overview of the oospore under SEM. 35. Granular aspect of the osospore wall under SEM.

FIGURES: 36–39. Chara rusbyana 36. Habit. The arrows indicates some broked branchelets. 37. Node of the thallus. The arrows points two tiers of stipulodes. 38. Ecorticated apical segment of a branchlet. 39. Ecorticated basal segment of two branchlets. The arrows point to stipulodes in two tiers.