Mycosystema. 2013, 32(3): 386-428.
Two terricolous species of the Australasian Discinella terrestris aggregate are reported from Mediterranean eucalypt plantations on the Iberian Peninsula. The two species were recorded in Spain since 1996–97, but were possibly imported several decades earlier, perhaps already during the mid-eighteenth century. Their obvious restriction to Eucalyptus, presumably by mycorrhiza, is discussed. One of them (here named Phaeohelotium undulatum) possesses a yellow-ochraceous hymenium and amyloid asci, whereas the other (Phaeoh. succineoguttulatum) deviates by an ochre-brown hymenium due to abundant, refractive, yellowish-brown vacuolar guttules in the paraphyses, and by consistently inamyloid asci. Both species have asci arising from simple septa, a Hymenoscyphus-type of apical ring, ascospores that turn brown when overmature, and a gelatinized ectal excipulum of prismatic to hyphoid cells. Ecologically the two taxa are very similar, though Phaeoh. succineoguttulatum is adapted to a little cooler and more humid climate, following its occurrence in the north and northwest of Spain, though both species were sometimes recorded at the same site in the centre and south of Spain. Our molecular analysis revealed that these two species and a specimen from New Zealand, here accepted as Phaeohelotium confusum, form a clade with Phaeoh. monticola (which is currently believed to be conspecific with the type of Phaeohelotium, Phaeoh. flavum), whereas a sequence gained by us from Discinella boudieri (type of Discinella) is quite distant from D. terrestris, clustering instead with Pezoloma ciliifera, a typical species of Pezoloma. The problematic generic limits around Hymenoscyphus, Cudoniella and Phaeohelotium are discussed. The Discinella terrestris aggregate is here transferred to Phaeohelotium, though this genus is apparently paraphyletic. Alternatively, Cudoniella or Hymenoscyphus could be extended to include the species of the Phaeohelotium clade. Based on morphological features as well as DNA sequences, we conclude that Gelatinodiscus is a synonym of Chloroscypha, and some species currently placed in Bisporella are better assigned to Calycina. Hence, we propose the following new combinations: Calycina claroflava, C. drosodes, C. lactea, C. languida, C. scolochloae, and C. subcitrina, Cyathicula amenti, Chloroscypha flavida, Phaeohelotium fulvidulum and Phaeoh. tamaricis. A restudy of type material of the D. terrestris aggregate, comprising the five Australasian taxa Helotium terrestre, Phaeopezia ochracea, Aleurina readeri, Pseudohelotium undulatum, and Discinella confusa, shows that four of them differ from those two species recorded from Spain in possessing croziers at the ascus base, besides showing a certain tendency to narrower asci and ascospores. Only Ps. undulatum from Tasmania was found to have simple-septate asci and is here tentatively considered conspecific with that Spanish species having a yellow disc. Aleurina readeri from Victoria deviates by consistently inamyloid asci. For the latter two taxa new combinations in Phaeohelotium are here proposed. The earlier asserted synonymy of Phaeopezia ochracea from Tasmania with the older H. terrestre from Queensland is confirmed, though the spores of the former are slightly longer and narrower. In order to avoid a homonym, a new name Phaeohelotium baileyanum is here proposed for H. terrestre. Discinella confusa from New Zealand differs only insignificantly from Phaeoh. baileyanum in a pale bluing around the strongly amyloid apical ring and in slightly narrower asci and slightly smaller spores. However, specimens here assigned to Phaeoh. baileyanum partly also showed such pale bluing. Although the two taxa are not clearly separable, the combination Phaeohelotium confusum is here proposed, based mainly on a different host and geographical distribution, also because of the consistent absence of brown spores. The D. terrestris aggregate shows a rather dense distribution in the forests along the southeast and southwest coast of Australia, and throughout Tasmania and New Zealand. A connection to a host tree is unclear in many of the known records. For D. confusa, a species from New Zealand, a connection to Nothofagus is certain. Phaeoh. baileyanum occurs in Australia and Tasmania, and a relation to Eucalyptus seems possible, while its type derives from a quite isolated site in eastern Australia. Since Eucalyptus is not native to New Zealand, the two Spanish species might originate from Australia or Tasmania. However, apart from the type locality in Tasmania, specimens referable to Phaeoh. undulatum were also discovered in New Zealand under Myrtaceae of the genera Kunzea and Leptospermum. In conclusion, the here reported heterogeneity of the D. terrestris aggregate demands a re-examination of all the many Australasian records under that name, specifically examination of the ascus base.
