Pleosporales » Dictyosporiaceae » Digitodesmium

Digitodesmium recurvum

Digitodesmium recurvum W. H. Ho, K. D. Hyde & Hodgkiss, Mycologia 91: 900 (1999)

 

Etymology: In reference to the recurved conidial arms.

 

Sexual morph: Undetermined. Sexual morph: Conidiomata sporodochial, scattered, punctiform, pulvinate, dark brown to black, 100–300 µm diameter. Mycelium mostly immersed in the substratum, composed of brown, smooth, thin walled, septate, branched hyphae. Conidiophores semi-macronematous, mononematous, pale brown, smooth, thin-walled, unbranched, cylindrical, flexuous, 6–14 × 3–5 µm. Conidiogenous cells monoblastic, integrated, terminal, determinate, pale brown, smooth, thin-walled, non-proliferating, giving rise to a single crop of conidia that mature synchronously. Conidia acrogenous, holoblastic, solitary, pale brown, chiroid, 30–45 × 12–21 µm (x̄ = 39 × 16 µm, n = 30), euseptate, with 4–7(–8) arms vertically inserted on basal cells in different planes; basal cells 3.5–6 × 3.5–5 µm, pale brown, truncate, smooth, thin-walled; arms discrete, unbranched, closely appressed to each other or divergent at maturity, cylindrical, 25–41 × 5–7 µm, 5–10-euseptate, slightly constricted at the septa, with conspicuous septal pores surrounded by marked pigmented rings 1–1.5 µm wide, appearing as dolipores in side view, mostly with a narrowed, recurved apical cell. Conidial secession schizolytic. (Ho et al. 1999)

 

Material examined: HONG KONG, Tai Po Kau Forest Stream, on submerged wood, 27 Jun 1996, K D. Hyde WH 300H 98 [HOLOTYPE: HKU(M) 4552], 27 Dec 1997, W. H. Ho H 639 [HKU(M) 8739]; ibid. on submerged Machilus velutina wood bait, 29 Mar 1997, W. H. Ho H 383 [HKU(M) 6043].

 

Freshwater distribution: China (Ho et al. 1999)

 

References

Ho WH, Hyde KD, Hodgkiss IJ (1999) Digitodesmium recurvum, a new species of chirosporous hyphomycete from Hong Kong. Mycologia 91:900–904

 

Figs. 1–9. Digitodesmium recurvum (from HOLOTYPE). 1. Colonies on woody substratum, 2. A sporodochium with conidial mass attached to conidiophores, 3. Conidiophores viewed from above, illustrating their circular lumina, 4. Mass of conidiophores. Note that the arrowed conidiophore is in side view, 5. Conidia with parallel euseptate arms vertically inserted on basal cells in different planes. Note that the arms of the conidium are closely appressed, while another is slightly divergent, 6. Conidia with divergent arms. Note that the arms are recurved at the apex, 7. Closer view of the lower portion of a conidium. Note the conspicuous conidial septal pores surrounded by marked pigmented rings (R). The rings appear as dolipores (D) in side view, 8. Conidium at the basal portion illustrating the pigmented rings (R) at the conidial septum, 9. Basal portion of a conidium, illustrating the pigmented ring of conidium delimiting septum. The ring appears as dolipore-like (D) in side view. Scale bars: 1 = 500 µm, 2 = 20 µm, 3–6 = 10 µm, 7–9 = 15 µm. (Ho et al. 1999)

 

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