Metacapnodium adamantinum S. Hughes & T. J. Atk.

Fig. 4

Specimen examined.

USA • Oregon, Coos County, vicinity of Eel Creek Campground, 2–4 km from Pacific Ocean Dunes, elevation: 5–25 m, 43.5883°N, 124.1900°W, on twigs of Arctostaphylos sp., Aug. 2000, B. McCune, OSC 169460.

GenBank accession number.

ITS, OR 532928.

Description.

Subicula brown to dark brown, superficial. Mycelia of brown, moniliform, straight to curved hyphae, tapered towards the ends. Cells broader than long, (14 –) 20–25 (– 29) µm wide, 12–22 µm long, distal, narrowest cells 10–12 µm wide.

Sexual form. Ascomata dark brown to black with short moniliform appendages scattered in the subicula, 450–500 µm long, 300–350 µm wide. Asci bitunicate, 8 – spored, 120–160 × 30–40 µm. Ascospores hyaline to pale brown when immature and brown at maturity, diamond shaped, biseriate, in some cases germinating with phialides (Fig. 4 E). Ascospores with 8–12 transverse septa, up to 5 longitudinal septa, and overall size (40) – 57.7 – (90) + / – 11.3 × (15) – 18.0 – (27) + / – 2.4 µm, N = 30.

Asexual form. Capnophialophora – Phialides on ascospores or on hyphae, pale brown to brown, venter subglobose, 6–8 µm wide, collarette subcylindrical, 3–4 × 2–4 µm.

Hosts and geography.

The holotype grew on trunks of Leptospermum scoparium (Myrtaceae) in New Zealand and the host of specimen OSC 169460 was an Arctostaphylos sp. in Oregon, USA.

Notes.

Phylogenetically (Fig. 2), M. adamantinum forms a clade with M. novae-zelandiae and M. ericophilum, even though it apparently lacks the capnocybe form present in the two related species. Among taxa in Metacapnodiaceae, ascospores in two published species, M. adamantinum S. Hughes & T. J. Atk. and M. gemmiferum S. Hughes & T. J. Atk. are consistently dictyoseptate, distinguishing this from other species that have ascospores with transverse septa only. Hughes et al. (2012) mentioned an unpublished new Metacapnodium species on Vaccinium in Oregon, collected by Jeffrey Stone, which has dictyoseptate ascospores and an unknown relationship with M. adamantinum. Metacapnodium adamantinum can be distinguished from M. gemmiferum by having larger ascospores and more transverse and longitudinal septa (Hughes et al. 2012).