Ustilago maydis
investiganda
f. cul.
Ustilago maydis investiganda
investiganda: Owed an investigation. The species is on the Needs Investigation table because a question stands on its published record that the Key cannot read a verdict from: a poisoning reported and no molecule found, a molecule found and no sourced route, a mark in a source list, a molecule known from this one species and not yet confirmed. The name is the stem of its recorded molecule, where the record names one and decides it, then investiganda, and nothing after it while the row is open. Where the record names no molecule the name is investiganda alone, and the gap is deliberate. The Key reads molecules: it puts a molecule in a name only when a record has placed that molecule in the mushroom. A poisoning report is not such a record; it says that harm occurred, not what caused it. The molecule may well exist, and the word states that it is to be found, not a guess at what it will be. The species is not innocuus, because innocuus means that the published record carries no link to a toxic molecule, and this species is on the table because the question of such a link is open; it would be innocuus only once the question is closed in that direction. The species leaves the table, and the word, by a ruling: its molecule registered and read, or its record found to carry no molecule after all. Latin, the gerundive of investigare: to be investigated.
On Needs Investigation, Medicinal Use, The Complete Table.
GBIF: photographs, names and where it has been found.
Sources
| Li et al. 2021 | 6 reports of eating without harm Li H, Tian Y, Menolli N Jr, Ye L, Karunarathna SC, Perez-Moreno J, Rahman MM, Rashid MH, Phengsintham P, Rizal L, Kasuya T, Lim YW, Dutta AK, Khalid AN, Huyen LT, Balolong MP, Baruah G, Madawala S, Thongklang N, Hyde KD, Kirk PM, Xu J, Sheng J, Boa E, Mortimer PE (2021). Reviewing the world's edible mushroom species: a new evidence-based classification system. Comprehensive Reviews in Food Science and Food Safety 20: 1982-2014. Supplementary Table S1. link |
| Wu et al. 2019 | ‘Treating hepatopathy and neurasthenia’ — Wu et al. 2019, Table 1, p. 50, citing Dai et al. 2009 Wu F, Zhou L-W, Yang Z-L, Bau T, Li T-H, Dai Y-C (2019). Resource diversity of Chinese macrofungi: edible, medicinal and poisonous species. Fungal Diversity 98: 1-76. doi:10.1007/s13225-019-00432-7. Table 1, 'Medicinal fungi and their function(s)'. link |
| Boa E 2004 | ‘food(m)’ — Annex 3 Boa E R (2004). Wild edible fungi: a global overview of their use and importance to people. Non-Wood Forest Products 17. Rome: FAO. ISBN 92-5-105157-7. link |
Needs Investigation. Why it is here: Tricholomic acid (formerly M37) is reported in this species and may be of concern. It was removed from the molecule table on 2026-10-09 because WR had never approved it (it was registered before Rule 3), so the species has no molecule and no verdict. Earlier (2026-10-05): its kitchen route rested on an unsourced determination for M37 Tricholomic acid: no paper, passage or recipe behind it (no source on record). What would settle it: William Rubel evaluates whether Tricholomic acid harms a person by mouth, eaten raw, at the portion (Rule 3). If he registers it, the molecule and this link return. The link's source, as recorded: Valverde, Paredes-Lopez et al. (1996) J. Agric. Food Chem. 44(9):2556-2559, doi:10.1021/jf960017u. Free amino acids extracted (MeOH/CHCl3/water), cation-resin purified, derivatized to N-TFA-N-methyl esters, and analyzed by capillary GC and GC-MS; tricholomic acid reported among the detected free amino acids (RI ~30.89), identified by mass-spectral comparison. Genuine analytical detection in this species (not taxonomic inference). Held at medium not high: single report; identification of an unusual isoxazoline amino acid within a routine amino-acid GC-MS profiling run (library/literature-spectrum matching) is less definitive than a dedicated isolation/structure study; and U. maydis is a basidiomycete phylogenetically distant from Tricholoma, so independent confirmation would strengthen it. Earlier: Find a source for how M37 Tricholomic acid behaves in water and heat. With a source the determination returns and the species to its route.
Medicinal Use. Medicinal use: Treating hepatopathy and neurasthenia (Wu et al. 2019, Table 1, p. 50, citing Dai et al. 2009). Listed as medicinal: Boa 2004, Annex 3, (m); Boa 2004, Annex 3, food(m). Under investigation: see Needs Investigation.
Cite this pageRubel, William. 2026. “Ustilago maydis.” Taxonomy of Toxins. Last modified 24 October 2026. https://taxonomyoftoxins.com/species/ustilago-maydis/