CHOIROMYCES MAGNUSII (Mattirolo) Paoletti 1889
in Saccardo's Syll. fung. VIII: 901
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Basionym:
Terfezia magnusii Mattir Mem. Accad. Scienze, Torino, ser. 2 37: 16 (1887)
Synonyms:
Choiromyces gangliformis Vittad., (1831) sensu Ceruti, Icon. Mycol. Bresadola 28 suppl. 2: 19, tab 19, (1960) non Vittadini
Macroscopic characters:
Ascomata: hypogeous or subhypogeous, subglobose, irregularly lobed, gibbous, deeply sulcate, 2–8(–12) cm in size, smooth, initially whitish, becoming ochre or brown, with adhering soil.
Gleba: hard, whitish at first, brown at maturity, marbled with sterile, white, sinuous veins that do not completely surround the fertile areas.
Odour: faint, distinctive.
Taste: mild, pleasant, not very persistent.
Edibility:
Highly prized in parts of Extremadura and Andalusia (Spain), where Choiromyces magnusii is known locally as criadilla jarera.
Habitat:
A spring species that grows in dry, acid soil, always associated with Cistus ladanifer. Although it develops underground, its presence can be detected through the cracks that form in the soil as the ascomata grow.
Notes:
Although Ceruti synonymises Choiromyces gangliformis Vitt. with Choiromyces magnusii, its strong, unpleasant odour, with a ripening period in summer and autumn, is more reminiscent of Choiromyces meandriformis. Vittadini himself admitted that both species are barely distinguishable and that Choiromyces gangliformis could be considered a particular form of Choiromyces meandriformis rather than a distinct species.
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Microscopic characters:
Asci: elongate-clavate, arranged among paraphyses in an irregular hymenium, 150–160(–200) × 40–60 µm, thick-walled (up to 2.5 µm thick), 8-spored, not stained in Melzer’s Reagent.
Paraphyses: hyaline, septate, cylindrical, up to 8 µm diam. towards the apex.
Ascospores: 17–25 µm, globose, yellow at maturity, ornamented with low (<1 µm), hemispherical warts, giving them a golf ball-like appearance.
Peridium: 100–200 µm, composed of interwoven, hyaline hyphae, yellowish in the outermost layers, more or less inflated.
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