Leaf-inhabiting genera of the Gnomoniaceae, Diaporthales - CBS

Le a f-i n h a b i t i n g g e n e r a o f t h e Gn o m o n i a c e a e, Di a p o r t h a l e s
Fig. 44. Morphology on natural substrates, asci and ascospores. A. Plagiostoma euphorbiae, lectotype Fungi Rhenani 863, BPI bound. B, C. P. aesculi, epitype BPI 748430.
D–F. P. barriae, holotype BPI 877717B. Scale 10 μm.
Type species of Plagiostoma and synonymous
genus, Cryptodiaporthe
Plagiostoma euphorbiae (Fuckel) Fuckel, Jb. Nassau Ver. Naturk.
23–24: 118. 1870. Figs 43A–C; 44A; 45A–F.
≡ Sphaeria euphorbiae Fuckel, Enumeratio fungorum Nassoviae: 69.
1860.
≡ Gnomonia euphorbiae (Fuckel) Sacc., Michelia 2: 312. 1881.
≡ Gnomoniella euphorbiae (Fuckel) Sacc., Syll. Fung. 1: 418. 1882.
= Gnomonia tithymalina Sacc. & Briard, Revue mycol. 7: 209. 1885 fide Monod
1983.
Perithecia solitary, without stroma, randomly scattered on dead
stems, black, suboblate to oblate-spheroidal when moist, 230–350
µm high × 290–430 µm diam, convex when dry. Necks central or
eccentric, short, only slightly projecting from plant tissue, 70–95 µm
long, 80–90 µm diam. Asci oval, (33–)37.5–41(–52.5) × 10.5–12.5(–
13.5) µm (mean = 41 × 12, SD 7.5, 1.5, n=5), apical ring 2.5–3 µm
diam, with eight ascospores arranged obliquely uniseriate, obliquely
biseriate ot irregularly multiseriate. Ascospores ellipsoidal, straight
or inequilateral, (12–)13–13.5(–15.5) × (3–)3.5(–4) µm (mean
= 13.5 × 3.5, SD 0.5, 0.2, n=33), l:w (3.1–)3.7–4(–4.5) (mean =
3.9, SD 0.3), two-celled, not constricted at septum; septum located
at (42–)45–49(–56) % (mean = 47, SD 3) of ascospore length;
cells with parallel walls, rounded at ends, each cell with two large
guttules; appendages absent.
Cultures: Colonies on PDA attaining 60 mm diam after 40 d at 23
°C, flat, glabrous to velvety, dark brown to greyish brown; margins
submerged, orange-grey; margin irregular; reverse dark brown to
brownish orange. Colonies on MEA attaining 90 mm after 40 d at 23
°C, flat, superficial and partly submerged, with no aerial mycelium,
thin, consisting of dendroid branches, shades of orange-grey,
brownish orange, brownish grey; margin irregular; reverse of same
colours as surface. Colonies on MYA attaining 90 mm after 40 d
at 23 °C, flat, short felty orange-grey in central part, glabrous to
velvety, dark brown; margin submerged, greyish orange, irregular;
reverse dark brown to brownish orange.
Habitat: On dead stems of Euphorbia palustris L. and E. pannonica
Host (Euphorbiaceae).
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