Flora of New Zealand Series

≡*Delisea pseudosticta Fée, Essai crypt écorc.: ci (1825).

=*Celidium dubium Linds., Trans. Roy. Soc. Edinb. 24 (2): 449 (1866).

≡*Homostegia dubia (Linds.) Cooke, Grevillea 13: 66 (1885).

Description : Lichenicolous. Ascomata forming distinct galls on host thallus, galls constricted at base, 0.5–5 (–7) mm diam. Stromatic tissue dark greenish brown, with a warty surface, forming a layer 25–45 μm thick over the hymenium and a layer 35–70 μm thick below the hymenium, and also present between hymenial loculi. Hypothecium brown. Hymenium 40–70 μm thick. Asci 4–8-spored, 25–32 × 5.6.5 μm. Ascospores 3-septate, 16–25 × 4–9 μm. Pycnidia immersed in stroma, ostiole erumpent, wall dark-brown, irregular, 40–50 μm diam., 80–90 μm tall. Conidia 4.5–5.5 × 1 μm.

N: North Auckland (Poor Knights Is) to Wellington. S: Nelson to Southland. St: (Pegasus Creek Port Pegasus). Throughout, widespread, forming conspicuous galls on host lichens. Known also from Tasmania and southern Chile (Ertz et al. 2005: 94).

Austral

Hosts : Pseudocyphellaria glabra in New Zealand and Tasmania; P. glabra and P. freycinetii in southern Chile (Ertz et al. 2005: 94).

Illustrations : Fée (1825: tab. 2, fig. 15 – as Delisea pseudosticta); Lindsay (1866c: pl. XXX, figs 47–42 – as Celidium dubium); Hawksworth & Galloway (1984: 87, fig. 1A, B fig. 2A, B); Ertz et al. (2005: 93, fig. 71).

* Celidium dubium. Lauder Lindsay (1866c: 449–450) cites several Otago localities where he collected this taxon, ("Parasitic on the thallus of various species of Sticta" [=Pseudocyphellaria]) from which a future lectotypification of the name may be made. They are as follows; (1) "Signal Hill, Dunedin, on S. granulata"; (2) "On S. fossulata Duf. (fructiferous and sterile specimens); corticolous (on trees), Saddlehill Bush"; (3) "On S. rubella, Hook. and Tayl. (sterile specimens), on trunks of dead trees. Greenisland Bush". Lindsay further commented "It remains for the Local Botanist to determine whether it is the same parasite, which affects S. granulata, S. fossulata, and S. rubella; whether all the forms of the Perithecia, Sori, and Maculae above described, are referable to a single plant." (Lindsay 1866c: 450). Hawksworth et al. (2004: 192) refer Celidium dubium to Plectocarpon pseudosticta.

* Plectocarpon pseudosticta is characterised by: the lichenicolous habit; the distinctive, erumpent, galls produced on both upper and lower surfaces of the host; the distinctive warty darkened stromatic tissue forming a layer above and below the hymenium; and colourless, 3-septate ascospores, 16–25 × 4–9 μm.