Fungalpedia – Note 50 Lactifluus
Lactifluus (Pers.) Roussel
Citation if using this entry: Bera et al. (2023) Basidiomycota. Mycosphere (in prep)
Index Fungorum, MycoBank, GenBank, Fig. 1
Persoon (1800) originally presented the name Lactifluus as a section under Agaricus. After Buyck et al. (2008) marked the revolutionary alterations in the generic concept of Russulaceae based on nrITS, nrLSU and rpb2 sequence data, the species belonging to the some of the pre-existing subgenera of the genus Lactarius [L. subg. Gerardii Stubbe, L. subg. Lactifluus (Burl.) Hesler & A.H. Sm., L. subg. Lactariopsis (Henn.) R. Heim, L. subg. Russulopsis Verbeken, L. sect. Edules Verbeken and L. sect. Panuoidei Singer] are now treated under the name, Lactifluus which was raised at the generic level (Buyck et al. 2008, 2010). Lactifluus volemus (Fr.) Kuntze is the type species. Thereafter, Verbeken et al. (2011, 2012a, b) and Stubbe et al. (2010, 2012) published new combinations for all the subgenera of Lactifluus for a clear overview. The basidiomata of this genus can be both agaricoid or pleurotoid with the brittle consistency (Van de Putte 2012, Verbeken & Nuytinck 2013). The colour varies from white to yellowish white to orangish or brownish tones. The pileus is generally azonate and ranges from convex to hemispheric to infundibuliform shape. The surface texture can be smooth to rugulose or cracked at places and is usually dry, and velvety. Lactifluus is characterized by the presence of latex, usually milky in consistency (Van de Putte 2012, Verbeken & Nuytinck 2013). The colour of the latex is mostly white to yellowish white which sometimes turns the colour of the lamellae and context into orangish to brownish when exposed (Van de Putte 2012, Verbeken & Nuytinck 2013). The basidiospores are globose to elliptical in shape with amyloid ornamentation (Van de Putte 2012, Verbeken & Nuytinck 2013). The lamellar trama is composed of lactifers, sphaerocytes and connecting hyphae (Van de Putte 2012, Verbeken & Nuytinck 2013). The hymenial cystidia in Lactifluus can be thin-walled or thick-walled. The pileipellis and stipitipellis can be of various hyphal arrangements or only pseudoparenchymatous cells or combination of both with presence of thick-walled terminal elements in some species. Clamp connection is completely absent. They are usually ectomycorrhizal with subtropical to sub-temperate forest trees (Van de Putte 2012, Verbeken & Nuytinck 2013). A thorough study of Lactifluus on a global level covering its biodiversity, biogeographical distribution, evolution, morphological variations, taxonomy, and ethnomycological uses was published by De Crop et al. (2021). To date, the genus has 221 species discovered worldwide (De Crop et al. 2021) to date.
Type species: Lactifluus volemus (Fr.) Kuntze
Fig 1. Lactifluus volemus (holotype) a. Basidiomata. b. Basidiospores. c. Pleurolamprocystidia. d. Cheilolamprocystidia. e. Pileipellis. Scale bars: b-e = 10 μm. Drawn from Van de Putte 2012.
References
Buyck B, Hofstetter V, Eberhardt U, Verbeken A, Kauff F 2008 – Walking the thin line between Russula and Lactarius: the dilemma of Russula subsect. Ochricompactae. Fungal Diversity, 28, 15–40. https://www.semanticscholar.org/paper/Walking-the-thin-line-between-Russula-and-the-of-Buyck-Hofstetter/a31d2ab2daa2e939f21ec066af592834bfcd3e32
Buyck B, Hofstetter V, Verbeken A, Walleyn R 2010 – Proposals to conserve or reject names. 1919 Proposal to conserve Lactarius nom. cons. Basidiomycota with a conserved type. Taxon, 59(1), 295–296. https://www.cabdirect.org/cabdirect/abstract/20198647876
De Crop E, Delgat L, Nuytinck J, Halling RE, Verbeken A 2021 – A short story of nearly everything in Lactifluus (Russulaceae). Fungal systematics and evolution, 7(1), 133–164. https://pubmed.ncbi.nlm.nih.gov/34124621/
Persoon CH 1800 – Tentamen dispositionis methodicae fungorum in classes, ordines, genera et familias. Cum supplemento adjecto. Arcum Caeci. https://www.biodiversitylibrary.org/bibliography/42674
Stubbe D, Nuytinck J, Verbeken A 2010 – Critical assessment of the Lactarius gerardii species complex (Russulales). Fungal Biology, 114(2–3), 271–283. https://www.sciencedirect.com/science/article/abs/pii/S1878614610000103
Stubbe D, Wang XH, Verbeken A 2012 – New combinations in Lactifluus, 2: L. subg. Gerardii. Mycotaxon, 119, 483–485. https://biblio.ugent.be/publication/2939779
Van de Putte K 2012 – Hidden diversity exposed – a case study of Lactifluus volemus sensu lato. Doctoral dissertation, Ghent University. https://www.mycology.ugent.be/content/hidden-diversity-exposed-case-study-lactifluus-volemus-sensu-lato
Verbeken A, Nuytinck J 2013 – Not every milkcap is a Lactarius. Scripta Botanica Belgica, 51, 162–168. https://fungi.fr/Html/VerbekenNuytinckLactarius.pdf
Verbeken A, Nuytinck J, Buyck B 2011 – New combinations in Lactifluus. 1. L. subgenera Edules, Lactariopsis, and Russulopsis. Mycotaxon, 118, 447–453. https://www.ingentaconnect.com/content/mtax/mt/2012/00000118/00000001/art00051
Verbeken A, Nuytinck J, Buyck B 2012a – New combinations in Lactifluus. 1. L. subgenera Edules, Lactariopsis, and Russulopsis. Mycotaxon, 118, 455–458. https://biblio.ugent.be/publication/2122219
Verbeken A, Van de Putte K, De Crop E 2012b – New combinations in Lactifluus. 3. L. subgenera Lactifluus and Piperati. Mycotaxon, 120, 443–450. https://www.ingentaconnect.com/content/mtax/mt/2012/00000120/00000001/art00053
Entry by
Ishika Bera, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
(Edited by Kevin D Hyde)