Polysphondylium tenuissimum H. Hagiw., Bull. Natn. Sci. Mus.

Liu, Pu & Li, Yu, 2017, Dictyostelids from Jilin Province, China II, Phytotaxa 323 (1), pp. 77-82 : 80

Polysphondylium tenuissimum H. Hagiw., Bull. Natn. Sci. Mus. , Tokyo, Ser. B, 5: 69-72 (1979).

Sorocarps ( Fig 2A ) solitary or gregarious, not phototropic, erect or inclined, sometimes prostrate. Sorophores colorless, sinuous, 3.5–9.5 mm high, terminal segments of sorophores not elongate, gradually tapering from bases to tips, bases ( Fig 2B ) clavate or digitate, tips ( Fig 2D ) subulate; with 3–21 nodes, each whorl with 3–5 branches. Branches ( Fig 2C ) tapering from bases to tips, bases clavate, tips acuminate, usually 120–200 μm long. Sori white, globose, terminal sori 30–80 μm diam, lateral sori 20–50 μm diam. Spores ( Fig 2E ) hyaline, elliptical to oblong, mostly 5.0–7.5 × 2.5–3.7 μm, with polar granules. Cell aggregations radiate in pattern. Pseudoplasmodia do not migrate. Macrocysts ( Fig 2F ) 6.3–10 μm diam.

Cultures examined. HMJAU MR064. Strain 0073–4 isolated in 2009 from a broadleaf forest soil (365 m elevation), collected in Wangqing National Nature Reserve, Jilin Province, China, in the same year.

Known distribution. U.S.A., Guatemala, Japan, and China.

Commentary. Polysphondylium tenuissimum is characterized by a large number of whorls, short branches, and small sori. Spores of this species, based on the isolate obtained in the present study, are slightly larger than the original report of 5.0–6.2 × 2.7–3.5 μm ( Hagiwara 1989).

Figures

FIGURE. 2 Polysphondylium tenuissimum (A–F) and Dictyostelium brefeldianum (G–K): A, G, sorocarps; B, H, sorophore base; C, sorophore branch; D, I, sorophore tip; E, J, spores; F, macrocysts; K, myxamoebae. Bars: A = 2 mm; B, C, D, E, F, H, I, J, K = 10 μm; G = 3 mm.