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Ionaspis ventosa P.M. Jørg. & R. Sant.
Family: Hymeneliaceae
Ionaspis ventosa image

Thallus crustose, growing in small patches to 5 mm diam. in cracks of rocks, greyish (in the herbarium).  Photobiont Trentepohlia, individual cells 20-25 µmlong. Apothecia pale olivaceous carneous to orange,immersed in the thallus, 0.1-0.2 mmdiam. with indistinct proper exciple in upper parts, widening considerably to 3040 µm below the subhymenium, forming a +/- paraplectenchymatous structure, I + persistently deep blue; hymenium olivaceous brown in upper parts, K + pinkish violet, I + blue-green, 40-50 µmdeep; paraphyses indistinct, partly branched, 13-2 µmwide; asci clavate with apical tholus without any amyloid structures 30-40 X 10- 12 µm, 8-spored. Spores colourless, globose, simple, 8-10 x 6-8 µm. Pycnidia unknown.- Fig. 3.

Ecology and distribution: Growing on acidic rocks in wind-swept mountain summits, free from snow in winter.  In Sweden associated with: Lecidea haerjedalicaPseudephebe miniusculaRhizocarpon intersitumRimularia impavida and Tremolecia atrata etc. (see Magnusson 1948: 408-411). The Icelandic specimens are associated with Rhizocarpon spp. and Tremolecia atrata, indicating a similar ecology.

Surprisingly it has also proved to be present at high levels in Peru, 4000-4100 m, growing on a large, exposed boulder on a rocky alpine slope with Buellia sp. (B. aethalea-group) and Caloplaca sp. This indicates that I. ventosa is a widespread, overlooked species, growing in a habitat where Ionaspis-species are normally not found.

Taxonomic notes: This species was first discovered by Magnusson (1948: 409) who identified it as I. carnosula (Arnold) Arnold, certainly due to the small size of the samples and the distinct I blue reaction in parts of the apothecium. The species, however, clearly belongs in the I. odora-group on account of the hymenial pigment giving a K pinkish violet reaction, and the general appearance. It differs clearly from I. odora and the other species in the group by the I deep blue exciple, and the globose spores. The apothecia often have a characteristic orange colour, which may be caused by iron.