Tetracladium sp.

Kravetz, Sebastián, González, Beatriz, Marano, Agostina & Giorgi, Adonis, 2018, The genus Tetracladium in Pampean streams (Buenos Aires, Argentina), Phytotaxa 338 (3), pp. 276-284 : 281

Tetracladium sp. (Fig. 5a–b)

Conidia with digitiform, acicular, globose and filiform appendicular elements developed from a central axis (32–48 × 2.5–3.5 μm). Primary branches arising at four or five levels. Two secondary acicular branches, inserted in the base of the acicular elements at first level (22–45 × 0.7–1.7 μm). At the axis base, stinger-shaped cell (9–13 × 1.3–2.5 μm) without basal extension, then in each following cell on the central axis, two appendicular elements arise that develop in the same plane in opposite form: at the first cell arise two acicular elements 3–4-septate (27–33 × 2–2.7 μm), and perpendicular to a third filiform element also 3–4-septate; at the second level of branchings arise two obclavateacicular elements 2–3-septate (19–22 × 2.5–3.7 μm); from the third level two digitiform elements of 1–2-septate (15–18 × 2–2.5 μm) are developed. In the fourth level the digitiform elements (8–11 × 2–2.3 μm) are bicellular. In the fifth level the globose elements are unicellular (2.5–3.5 × 1.5–2.7 μm). Distally with globose cell (2.7–3.5 × 1.5–2.7 μm). Its symmetry with respect to the central axis gives the appearance of a candelabrum.

Specimens examined:— Buenos Aires, San Andrés de Giles, Giles stream, 34° 27´17.284´´ S, 59° 27´27.91´´ W, 0–50 m, 17 September 2017, Kravetz, S.106 (slide BAFC 52789 ) ; ibid., Kravetz , S. (slide UNLu 105) .

Notes:— Due to their morphological characteristics, these conidia can undoubtedly be attributed to Tetracladium but do not match those of the species described so far. The most similar species is T. palmatum , however, the number of appendices and levels of branches of the axis in the conidia of our form is greater than in T. palmatum .