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 Add this item to the list  Antrodiella romellii (Donk) Niemelä
   
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Remarks (internal):The species is characterised by resupinate basidiocarps, large spores and agglutinated tramal hyphae. Antrodiella pachycheiles has similar spores, but it is pileate, its hyphal structure is different and skeletals swell and eventually dissolve in KOH. Antrodiella subradula (see below) is fairly similar but its spores are shorter and narrower and its tramal hyphae are separate, not agglutinated.
Donk (1967) proposed the name Poria romellii for a resupinate species that was featured by Romell (1926) and Eriksson (1949) as 'Poria byssina (Schrad.) Fr.' In a thorough analysis Donk concluded that the name P. byssina must be typified elsewhere, and hence he gave a nomen novum, Poria romellii, for the taxon now included in Antrodiella. Donk emphasised that his species concept was based on texts and illustrations by Romell and Eriksson-and, in particular, the 'excellent' drawing by Eriksson (1949, Fig. 1). Accordingly, he designated the holotype (L 0117094) from the specimens that Romell and Eriksson had studied and identified in Persoon's herbarium.
We restudied the holotype; the specimen is a young basidiocarp, substerile, and partly mould-contaminated. Salient characters could be seen, however. There are 3-4 thin, resupinate, cream-coloured basidiocarps arising from the bark of (evidently) Corylus avellana. Pores are round, (5-)6-7 per mm. Only collapsed basidia with four sterigmata, and a few turgid spores (3.8-4.7 x 2.7-2.8 µm) were found. Hyphal system is dimitic, generative hyphae thin-walled and clamped, skeletals weakly cyanophilous and 2.2-3(-3.8) µm thick, no basal layer, no gloeocystidia. Trama is largely monomitic due to the young age of the basidiocarp; tramal tissue is dense and hyphae are subparallel. These characters match with the description and drawing by Eriksson (1949) and with the present concept of the species.
Since the type material is scanty and in a poor condition, its value as research material is inferior in a group where exact spore dimensions are the most important criteria for a species concept. In order to settle the identity of the species, we here select an epitype for Poria romellii, specimen Niemelä 4018 (L, H). This specimen is strikingly similar to the holotype, and in a good fertile condition. It was studied and sequenced by Johannesson et al. (2000) in their study of Antrodiella. Epitype's nuclear ribosomal RNA internal transcribed spacer (ITS) is deposited in GenBank (acc. no. AF126899).
Donk's concept of Poria romellii was mixed: we studied another specimen (L 0194116), determined by Donk, collected in 1963 by him in the Netherlands from a fallen branch of Quercus. That specimen has larger pores (3-5 per mm) and much narrower spores, about 3.7-4.8 x 1.9-2.3 µm, and it seems to be conspecific with the newly (Bernicchia 2005) described Antrodiella ichnusana.
 
Description type:Non-original description 
Description:Antrodiella romellii (Donk) Niemelä
Karstenia 22:11, 1982. Poria romellii Donk, Persoonia 5:84, 1967. Holotype: 'Boletus byssinus Schrad. (Fungus nascens), Herb. Pers.' (L 0117094, studied). Epitype (designated here): Finland, Uusimaa, Tammisaari, 1987 Niemelä 4018 (L, isoepitype H).
Annual, resupinate, soft leathery, when dry hard, basidiocarps 30-60 x 10-30 mm, irregularly roundish, usually emerging solitarily. Sterile margin narrow, matt, hygrophanous especially in upper half of the basidiocarp. Pores 5-7 per mm, when fresh hygrophanous translucent or (after dry period) cream-coloured, when dry cream-coloured or with an apricot tint; orifices entire. Section: subiculum 0.1-0.5 mm, cream-coloured, tubes concolorous or darker. Dimitic, generative hyphae with clamps, skeletals rather uniform, CB(+), IKI-, 1.7-3.7 µm in diam., in subiculum with spaced and interwoven structure, basal layer almost monomitic; tramal hyphae interwoven, agglutinated; skeletals with variably visible lumen. crystal clusters sometimes present in between hyphae; hyphal tips at orifices often slightly inflated; no clear cystidioles or gloeocystidia. Spores ellipsoid, thin-walled, CB-, IKI-, (3-)3.4-4.4(-5.1) x (2.2-)2.3-2.9(-3.1) µm, ventral side convex or (rarely) flat, never concave.
 
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