Camarosporium robiniicola Wijayawardene, Camporesi & K.D. Hyde, in Wijayawardene, Bhat, Hyde, Camporesi, Wikee, Ariyawansa, Chethana, Tangthirasunun, Chukeatirote & Wang, Phytotaxa 183(1): 21 (2014)

Index Fungorum number: IF 807935; MycoBank number: MB 807935; Facesoffungi number: FoF 00002

Etymology —Named after the host genus on which the fungus occurs.

Saprobic on dead branches of Robinia pseudacacia. Sexual state: Not observed. Asexual state: Conidiomata pycnidial, 210−240 μm diam., 180−220 μm high, solitary or gregarious, black, immersed, unilocular, with a papillate ostiole. Pycnidial wall many-layered, with outer thick layers composed of dark brown cells, with inner 5−6 wall layers composed of hyaline cells of textura angularis. Conidiophores absent. Conidiogenous cells enteroblastic, annellidic, short, obclavate, hyaline, smooth. Conidia 18−28 × 7−11 μm (mean = 20.2 × 9.1 μm, n = 20), oblong, straight to slightly curved, rounded at both ends, 4−6-transverse septate, with 1 longitudinal septum, muriform, smooth, pale to dark brown.

Culture characteristics — On PDA, fast growing, greyish white, circular, smooth margin, zonate, thin mycelia, attaining a diam. of 2−3 cm after 7 days at 18ºC.

Material examined — ITALY. Forlì-Cesena Province: Santa Lucia—Predappio, on dead branch of Robinia pseudacacia L., 5 February 2013, E. Camporesi, NNW IT 1047 (MFLU13-0327, holotype), living culture MFLUCC 13-0527 = ICMP 20049 = HGUP N3.

Notes — Saccardo (1884) introduced Camarosporium robiniae (Westend.) Sacc. (≡ Hendersonia robiniae Westend.) from Robinia pseudacacia. Morphologically, C. robiniicola is distinct from C. robiniae, which has shorter and narrower conidia (18−28 × 7−11 μm and 15−16 × 7 μm, respectively). Nevertheless, Ellis & Ellis (1985) mentioned that Cucurbitaria elongata has a conidial state in Camarosporium (conidial dimensions, 17−27 × 7−9 μm), but did not give a species name. Our molecular data analyses (Fig. 1) show that Camarosporium sensu stricto (including C. robiniicola) is unrelated to Cucurbitariaceae. However, Cucurbitaria elongata (Fr.) Grev. (AFTOL-ID 1568 and MFLUCC 14-0260) clustered together with Camarosporium species. Brunaud (1888) described Camarosporium pseudacaciae Brunaud, from the same host viz. Robinia pseudoacacia, with conidia of the same length as Camarosporium robiniicola, but more narrow (6−8 μm). Hence, a new species is introduced to accommodate our collection.

Figure 1. Camarosporium robiniicola (MFLU13-0340). A. Conidiomata on branch of Robinia pseudacacia. B, C. Cross section of pycnidia. D. Cross section at ostiole region. E. Pycnidium wall. F, G. Developing conidia attached to conidiogenous cells. H–P. Conidia. Q. Germinating conidium. Scale bar: B, C = 200 μm, D = 70 μm, E = 30 μm, F, G, I–Q = 15 μm, H = 30 μm.