Stigonema corticola, Sant’Anna, Célia L., Kaštovský, Jan, Hentschke, Guilherme S. & Komárek, Jiŕí, 2013

Sant’Anna, Célia L., Kaštovský, Jan, Hentschke, Guilherme S. & Komárek, Jiŕí, 2013, Phenotypic studies on terrestrial stigonematacean Cyanobacteria from the Atlantic Rainforest, São Paulo State, Brazil, Phytotaxa 89 (1), pp. 1-23 : 15

Stigonema corticola Sant’Anna, Kaštovský, Hentschke& Komárek, sp. nov. ( Figs 11–13 )

Strata aerophytica , fasciculata cum filis irregulariter et dense aggregatis, praecipue nigro-fusca. Fila irregulares, flexuosa, multiseriata, rarissime uniseriata, saepe in agglomerationes cellulis transientes, cum ramis numerosis curtis, plus minusve filis principalis similares, apice rotundatae, saepe cum cellula solitaria, irregulariter rotundata terminatae; fila 12–40 µm lata, ad apices 10–15 µm lata. Numerosae agglomerationes cellularum irregularium. Vaginae firmae, distinctae, homogeneae vel lammelosae, sine colore vel luteo-fuscae, apice clausae. Cellulae irregulariter sphericae, ad 10 µm in diametro, contentu fuscescente. Heterocytae solitariae, intercalares, praecipue laterales, hemisphaericae 5–6 × 6–7 µm. Hormogonia curta, uniseriata, cylindrica, cum cellulis curtis, apice separantur.—Habitatio: Aerophytice vel epiphytice, praecipue ad cortice arborum, minus quam superficie solis praesens, in sylvis in montibus " Mata Atlantica " dictis, provincia São Paulo, Brasilia.

Type:— Brazil. São Paulo: State Park of “Serra do Mar” ( Santa Virginia ), preserved sample collected on 22 February 2010, W.A. Gama Jr. and E.M. Caltran (Holotype SP 427515!); Ubatuba, 9 november 2002, C.L. Sant’Anna, M. T. P. Azevedo and J. Komárek (Isotype SP 427511!) .

Clusters of densely agglomerated filaments, not distinctly separated in the main filaments and branches. Filaments are mono- to polyseriate, relatively short, flexuous, sometimes wart-like, irregular, usually from 12 (monoseriate) to 40 (polyseriate) µm wide, ends of branches about 10–15 µm wide. Numerous stages with irregular cell agglomerations. Sheaths distinct, homogeneous or lamellate, hyaline to yellow-brown, closed at the ends. Cells irregularly round, up to 10 µm in diameter, apical cells usually solitary, larger and rounded from outside, cell content brownish. Heterocytes mainly hemispherical, usually lateral, rarely intercalar, 5–6 µm long, 6–7 µm wide.

Habitat:— On tree barks or in soil among mosses.

Etymology:— Species named according to the main occurrence on bark of trees.

Notes:— Stigonema corticola is an interesting stigonematacean type with closely agglomerated and frequently branched, uni-to multiseriate, isopolar filaments. The main filaments are only slightly recognizable and are very similar to the branches. Stigonema corticola probably belongs to the vicinity of S. minutum , but differs in morphology mainly because of the presence of an amorphous stage (agglomeration of cells with lateral heterocytes) in young individuals of S. corticola . In addition, both types differ in ecology, since S. minutum from northern Europe is typically epilithic, while the tropical S. corticola typically grows on tree barks or less frequently on soils.

Figures

FIGURE 11 A–M: Stigonema corticola. A: General aspect of a thallus. B, C: Branched filaments. D: Young filament. E: Branches with agglomerated cells. F–H: Details of apex. I: Filament with a lateral heterocyte. J: Detail of a multiseriate filament. K: Initial stages of branching near the apex. L: Formation of hormogonium. M: Apex after releasing hormogonium. Scales: 10 µm in A (use for A, E), B (use for B–D), F (use for F–H), I and J (use for J–M).

FIGURE 12 A–I: Stigonema corticola. A: Uniseriate filament with lateral heterocyte. B–D: Mostly uniseriate filaments. E: Richly branched filaments. F–H: Agglomerated cells. I: Formation of a hormogonium. Scales: 10 µm in A (use for A–I).

FIGURE 13 A–F: Stigonema corticola. A: Agglomerations of cells with branches. B, C: Branched filaments. D, E: Details of multiseriate filaments with heterocytes. F: Detail of apex. Scales: 10 µm.