Ophiochaeta raciborskii Penz. & Sacc., Malpighia 11: 406. 1897.

Paragaeumannomyces raciborskii has been collected on culms of Chusquea bamboo and other unidentified bamboo species, on palm wood and fruit, and decaying wood of unknown trees. The species has a pantropical geographical distribution and is probably the most commonly encountered species of the genus; it is known from Indonesia in Java and Central America in Costa Rica (Penzig and Saccardo 1897; Carroll and Munk 1964). Other collections published under this name, which may represent different species, originate from Asia in Thailand, the Caribbean in Cuba, Jamaica and Puerto Rico, Central America in Costa Rica and Panama, and South America in Ecuador, French Guiana and Venezuela (Huhndorf and Fernández 2005).

For descriptions and illustrations, see Carroll and Munk (1964). The holotype of P. raciborskii (Penzig and Saccardo 1897) originates from decaying wood in Java. In the protologue, the species was described with black, setose ascomata 250 μm diam, short-stipitate asci 130–150 × 9–10 μm and hyaline, multiseptate ascospores 60–70 × 3 μm. Carroll and Munk (1964) redescribed the species based on the holotype and an additional collection from Costa Rica as having setose, reddish-brown ascomata 250–300 μm diam, 13–16-septate ascospores 50–65 × 2–4 μm, and asci 70–100 × 10–13 μm. Huhndorf and Fernández (2005) introduced a broader species concept of P. raciborskii, which was based on numerous specimens of a tropical geographical distribution originating mainly from Central and South America. The species was characterised by setose, reddish, russet or brown ascomata (150–)200–450 μm diam with stiff, dark setae scattered over the entire ascoma or absent in some specimens, 7-septate ascospores (50–)60–100(–150) × 3–3.75(–4.5) μm, and short-stipitate asci (150–)180–250(–350) × 10–20(–27) μm.

Paragaeumannomyces raciborskiifideHuhndorf and Fernández (2005) shows a high degree of ITS sequence variability accompanied by a low phenotypic plasticity, which resulted in the species being polyphyletic and segregated into four lineages labelled Paragaeumannomyces sp. 1–4 (Fig. 2). Two anamorphic craspedodidymum-like morphotypes with and without setulae and a chloridium-like synanamorph have been experimentally linked to several strains of P. ‘raciborskii’ by Huhndorf and Fernández (2005). Although the in vitro anamorphic characters seem promising in becoming another important set of diagnostic features to distinguish species of Paragaeumannomyces, isolated strains often form sterile mycelium in vitro or they are difficult to isolate into living culture.