Flora of New Zealand Series

Holotype: New Zealand. South I., Nelson, "Brook Stream track", ad corticem arborum, 120 m, 23.v.1994, W. Malcolm s.n. – CHR. Isotypes – BM, CANB, DUKE, ESS, GZU, H, HO, M, PRM, TSB, UPS, VBI, Herb. K. Kalb, Herb. A. Vězda.

Description : Thallus squamulose, irregularly spreading, delimited by a white, byssoid prothallus, the hyphae arachnoid, to 3 μm thick. Squamules 0.7–1 mm diam. Apothecia pale-brown to brown, sessile, disc plane with a paler proper margin, at maturity convex, the margins excluded, 0.8–1.5 mm diam., 0.25 mm tall. Exciple colourless. Hypothecium pale-brownish. Hymenium colourless, 70–80 μm tall; the paraphyses tips forming a cloudy, brownish epithecium. Paraphyses 2 μm thick, the apices not thickened. Asci clavate. Ascospores simple, colourless, bacillar, 13–18 × 2–2.2 μm. Pycnidia rare, immersed in thalline verrucae. Conidia narrow, 12–25 × 0.25 μm.

Chemistry : Argopsin (minor).

S: Known only from the type locality.

Endemic

Illustration : Vězda (1995c: 5).

Exsiccati : Vězda (1995c: No. 200).

Phyllopsora malcolmii is characterised by: the corticolous habit; the green thalline squamules, surrounded by a white, byssoid prothallus; pale-brown apothecia; hymenium 70–80 μm tall, colourless, hypothecium pale-brownish; ascospores bacillar, 13–18 × 2–2.2 μm, and a chemistry of argopsin.