Paraconiothyrium archidendri Verkley, Göker and Stielow

Paraconiothyrium archidendri Verkley, Göker and Stielow View in CoL , Persoonia 32: 37 (2014)

Fig. 10 View Figure 10

Description.

Saprobic on a dead stem of Citrus maxima ( Rutaceae ). Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 100–150 × 100–170 µm ( x ̄ = 105 × 135 µm, n = 10), pycnidial, immersed to semi-immersed, dark brown to black, solitary to aggregated, globose to sub-globose. Conidiomatal wall 15–30 μm wide ( x ̄ = 17 µm), thick-walled, composed of several layers of brown to dark brown pseudoparenchymatous cells, cells towards the inside hyaline, arranged in a textura angularis, fusing at the outside indistinguishable from the host tissues. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 6–8 × 3–4 µm ( x ̄ = 6.4 × 3.2 µm, n = 20), discrete, hyaline, globose to doliiform, holoblastic. Conidia 5.8–7 × 3–4 ( x ̄ = 6.3 × 3.2 µm, n = 40) µm, variable in shape, subglobose to ellipsoid, rarely obovoid, ends rounded, aseptate, initially hyaline, becoming olivaceous-brown at maturity, contents with several small oil droplets, smooth-walled.

Known hosts.

Acer pentaphyllum , Alliaria petiolate , Cinnamomum camphora , Citrus maxima , Coffea arabica , Ginkgo biloba , Magnolia sp. , Picea glauca , Pinus tabulaeformis , Pithecolobium bigeminum and Prunus salicina ( Verkley et al. 2004, 2014; Damm et al. 2008; Paul and Lee 2014; Nakashima et al. 2019; Tennakoon et al. 2022; this study).

Known distribution.

Brazil, Canada, China, Japan, Korea, Myanmar, South Africa, and the United States ( Verkley et al. 2004, 2014; Damm et al. 2008; Paul and Lee 2014; Nakashima et al. 2019; Tennakoon et al. 2022; this study).

Material examined.

China • Guangdong Province, Shenzhen , on dead stem of Citrus maxima ( Rutaceae ), 21 December 2024, D. S. Tennakoon, DC 030 ( SZU 25-018 , new host record); living culture MBSZU 25-027 .

Notes.

Paraconiothyrium archidendri was initially introduced by Verkley et al. (2014) from Pithecellobium bigeminum in Myanmar. A multi-gene phylogeny indicates that our collection ( SZU 25-018 ) groups with other P. archidendri isolates, particularly closely related to the isolate CBS 168.77. Our collection shares similar morphological characteristics with P. archidendri by having pycnidial, immersed to semi-immersed, dark brown to black conidiomata, globose to doliiform conidiogenous cells, and subglobose to ellipsoid, olivaceous-brown, aseptate conidia ( Damm et al. 2008; Paul and Lee 2014; Verkley et al. 2014; Nakashima et al. 2019; Tennakoon et al. 2022). Thus, we identify our collection as Paraconiothyrium archidendri with a new host occurrence from Citrus maxima in China.