Inosperma bulbomarginatum Aignon , Yorou & Ryberg, 2021

Aignon, Hyppolite L., Jabeen, Sana, Naseer, Arooj, Yorou, Nourou S. & Ryberg, Martin, 2021, Three new species of Inosperma (Agaricales, Inocybaceae) from Tropical Africa, MycoKeys 77, pp. 97-116 : 97

2. Inosperma bulbomarginatum Aignon, Yorou & Ryberg sp. nov. Figs 2b , 4

Diagnosis.

Inosperma bulbomarginatum differs from I. flavobrunneum by the smaller size of its basidiomata and larger basidiospores. It is phylogenetically distinct from all other undescribed African Inosperma in Old World Tropical clade 2

Type.

Holotype. Benin, Borgou Province, N’dali Region: 09°45.73'N, 2°19.93'E, on soil in Woodland dominated by Isoberlina doka and I. tomentosa , 8 July 2013, leg. Martin Ryberg, Voucher (MR00357), GenBank accession: ITS (MN096190); LSU (MN097882) and RPB2 (MN200775).

Description.

Pileus 13-18 mm diam., undulating plane, fibrillose, margin rimose, orange-brown to somewhat cinnamon, greyish-white (8E5), splitting at edge. Lamellae 2-2.5 mm deep, moderately close, narrowly attached, pale grey brown (9B5) to dark brown (9D5), sinuate. Stipe 10-22 × 2-2.5 mm, central, equal, marginate bulb, white to pinkish-buff (7A2), velar remnants. Odour and taste not distinctive. Basidiospores (7.1) 8-12.1 (14) × (4) 4.2-6.7(7) μm, avl × avw = 9.6 × 5.4 μm, Q = (1.3) 1.2-2.3(2.6), avQ = 1.8, smooth, elongate, thick-walled. Basidia (25) 28-40 × 6-12 μm, tetrasporic. Cheilocystidia 20-25 × 10-12 μm, clavate, thin-walled hyaline. Pleurocystidia absent. Pileipellis a cutis, thin-walled hyphae, 3-12 μm diam., cylindrical. Stipitipellis a cutis with subparallel hyphae 3-15 μm diam., septate, filamentous, subhymenium of compact hyphae, any reaction of pileus surface in KOH not observed. Caulocystidia 25-60 × 7-20 μm, ovoid to obovoid, sometimes utriform, observed on the upper third of the stipe.

Distribution.

Currently known from Benin and Zambia.

Ecology.

Scattered in Woodland dominated by Isoberlinia doka and I. tomentosa .

Etymology.

Inosperma bulbomarginatum referring to the presence of a marginate bulb at the base of the stipe.

Additional specimens examined.

Benin, Collines Province, Kilibo Region: 8°32.74'N, 2°40.42'E, on soil in Woodland dominated by Isoberlina doka , 22 June 2017 in the Forest Reserve of Toui-Kilibo, leg. Aïgnon HL., Voucher (HLA0389) GenBank accession: ITS (MT534302). Benin, Tchaorou, Borgou Prov, Okpara Forest: 9°15.28'N, 2°43.38'E, on soil in Woodland dominated by Isoberlina doka , 13 June 2017, leg. Aïgnon HL., Voucher (HLA0373) GenBank accession: ITS (MT534301). Benin, Alibori Borgou Prov, Alibori Superieur Forest Reserve: 10°23.76'N, 2°5.15'E on soil in Woodland dominated by Isoberlina doka , 11 July 2017, in Forest Reserve of Alibori Supérieur leg. Aïgnon HL., Voucher (HLA0417), GenBank accession: ITS (MT534300) and LSU (MT560734).

Notes.

Inosperma bulbomarginatum is similar to Inosperma cervicolor (Pers.) Matheny & Esteve-Rav., by its orange-brown pileus, but differs from it by the smaller size of the basidiomata and basidiospores, as well as its ecological association with Fabaceae Lindley and/or Phyllanthaceae Martynov and extensive distribution in Tropical Africa. I. cervicolor is associated with Pinaceae Spreng. ex F. Rudolphi and distributed in Europe and North America.

Figures

Figure 2. Macromorphology of: A Inosperma africanum (HLA 0383) B Inosperma bulbomarginatum (MR 00357) C, D Inosperma flavobrunneum (HLA 0367). Scale bar: 1 cm.

Figure 4. Microscopic structures of Inosperma bulbomarginatum (MR 00357) A basidiospores B basidia C cheilocystidia D caulocystidia E pileipellis F stipitipellis. Scale bars: 3 μm (A); 5 μm (B); 10 μm (C-F).