Flora of New Zealand Series

Holotype: New Zealand. Auckland, Huia, on damp scoria rock on maritime cliff, c. 30 m above sea, S-facing aspect, 1981, J.K. Bartlett 22639a – Herb. Henssen (MB). Isotype – AK.

Description : Thallus olivaceous, fruticose, forming cushions 10 mm wide and to 5 mm tall, composed of densely aggregated cylindrical lobes with slightly tapering tips. Lobes 2.5–4 mm long, and 0.15–0.35 mm thick, terminal branches up to 0.5 mm long. Thallus hyphae reticulately arranged, 1.5–3.5 μm diam., cells of fusion up to 7 μm wide. Photobiont Nostoc, filaments 3–6 μm thick, accumulated underneath thallus surface, widely scattered elsewhere. Apothecia rare, developing between lobes, up to 2.5 mm diam., at first brown with prominent proper margin and slightly urceolate disc, at maturity disc becoming flat and blackish. Proper exciple at first annular, becoming secondarily cupular and 150–215 μm thick, strongly gelatinised, in parts violaceous, black-pigmented, cell lumina reticulately connected and 1–3.5 μm wide; plectenchyma between thallus and exciple 25–50 μm thick. Hymenium 140–170(–215) μm tall, finally divided by sterile strands, sometimes proliferating. Epithecium 25–35 μm thick, at first violaceous brown, secondarily dark-green. Subhymenial layer 115–165 μm thick. Asci 95–106 × 10.5–12 μm, (2–)8-spored, walls I+ blue. Ascospores globose to subglobose, with cerebriform epispore, 8.5–13 × 8.5– 12 μm. Pycnidia 0.1 mm diam., ostiole dark. Conidia 2.5–3.5 × 1 μm.

Chemistry : TLC−, all reactions negative.

N: Auckland (Known only from the type locality). Growing through Zygodon intermedium on a very porous, acidic scoria rock of recent volcanic origin; on a S-facing cliff exposed to salt spray, associating with Rhacomitrium crispulum.

Endemic

Illustrations : Henssen (1999: 119, pl. IA; 121, pl. IIA; 123, pl. IIID)

Ramalodium dumosum (the specific epithet refers to the thorn-brush habit of the pulvinate thallus) is a saxicolous, maritime species, characterised by: the pulvinate thalli composed of cylindrical lobes with slightly tapering tips; and the large, flat apothecia which soon become dark-pigmented.