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Summary: Also listed in Veined category. Features include 1) bright orange to reddish color and smoothly pimpled surface, 2) growth on distorted Russula brevipes (and other Russula and Lactarius spp.) whose gills are often reduced to blunt ridges, 3) anamorph not being found in nature, and 4) spores 30-50 x 4.5-8 microns, 2-celled, warted, and apiculate. The anamorph is not found in nature, (Poldmaa). The edibility [of firm specimens] is often rated highly, although there is no absolute assurance that the host species is edible, (Arora). Although it is reportedly edible, some experience intestinal upset: it is probably best avoided since the host fungus cannot be identified accurately, (McKnight). Hypomyces lactifluorum is reported from BC (Redhead(5) and common on BC foray lists). It is found throughout North America (Phillips), NS, MB, in majority of states in all 6 regions of US, including specifically IA, MI, NC, PA, Mexico, and Guatemala, (Poldmaa), known only from North America: WA, OR, ID, MB, NB, NS, ON, PE, PQ, AL, AZ, CO, CT, DE, FL, GA, IA, IL, IN, KS, KY, MA, MD, ME, MI, MO, MS, NC, ND, NH, NJ, NM, NY, OH, PA, RI, SC, TN, TX, VA, VT, WI, WV, Guatemala, Mexico, (Rogerson).
Fruiting body: a layer of roughened or pimpled, bright orange to orange-red to purple-red or occasionally yellow-orange tissue which is firm to the touch; overall shape of mushroom and parasite "often like an inverted pyramid"; flesh (of host) crisp, white, (Arora), sub
Microscopic: SPORE 30-50 x 4.5-8 microns, "spindle-shaped or shaped like caraway seeds", colorless, warted, 1-septate, (Arora), SPORE 35-40 x 4.5-7 microns, fusiform, prominently verrucose and apiculate (verrucae 1-1.5 micron high, apiculi 4.5-7.5 microns long, acute, straight or curved), 2-celled, septum median; ASCUS 200-260 x 5-10 microns, long cylindric, "apex thickened and with a pore"; PERITHECIUM 400-600 x 200-450 microns, immersed except for papilla, KOH+, "papilla averaging 120 microns high, 120 microns wide", perithecial wall 25-30 microns wide laterally, cells 7-15 microns long, about 5 microns wide, fusoid, walls 1.5 micron thick, nonpigmented, perithecial apex composed "of circular to elliptic cells tending to be arranged in files and with long axis parallel to long axis of perithecium", 5-15 x 3-7 microns, walls 1.5 micron thick, cells around the ostiolar opening 3-5 microns wide, clavate, ostiolar canal periphysate; subicular hyphae "3-5 microns wide, septate, much branched, branching very irregular, often at right angles, densely compacted but remaining filamentous, smooth", occasionally some cells swollen to 10 microns wide, KOH+ purple, (Rogerson), SPORE 35-45 x 5-8 microns, "fusiform, with one side sometimes flattened", verrucose ("verrucae low and confluent with each other, 1-1.5 microns high"), ends apiculate (apiculi 4.5-7.5 5m long, with acute tips), 1-septate (septum median); ASCUS 200-260 x 6-10 microns, "with apex thickened, penetrated by a pore"; PERITHECIA "caespitose, immersed in the subiculum except the papilla", 400-600 x 250-450 microns, "KOH reaction with the whole perithecium turning purple, reaction in the perithecial wall usually much weaker (or sometimes lacking) than in the papilla", perithecial wall 25-30 microns wide, perithecial papillae 120-220 microns high, 120-200 microns wide at base, 80-120 5m wide at top, tip obtuse, "of pseudoparenchymatous texture, with cells in divergent files, becoming narrower toward the ostiolar canal and more rounded towards the outer surface", cells at the surface 6-13 microns in diameter; subicular hyphae 3.5-8 microns wide, loosely interwoven to densely compacted, cells not swollen or occasionally swollen; anamorph in nature not observed; thick-walled cells absent, (Poldmaa)
Habitat / Range
usually on the fruiting bodies of Lactarius and Russula (especially Russula brevipes), whose gills are often reduced to blunt ridges, (Arora), usually covering the aborted cap, stem, and deformed gills of host, (Rogerson), formed all over the host's gills and stem, sometimes also in small patches on cap; hosts belonging to Russulales: Lactarius spp., Russula spp., (Poldmaa), fruits July to October (Lincoff), found on Lactarius torminosus, and also next to Lactarius volemus, (Schalkwijk-Barendsen), other known hosts include Lactarius piperatus, L. deceptivus, and L. vellereus, (McKnight)
Hypomyces macrosporus Seaver (found in WA, AL, CT, MD, NY, OH, SC, WV, Mexico) is distinguishable only by color (subiculum white to buff, perithecia buff to yellowish amber) and negative reaction to KOH and may be merely an albino form of this species: orange specimens of H. lactifluorum have been found mixed with specimens that were variously white, white with orange streaks and orange-red with white streaks, but only the reddish streaks of the whitish form became purple in KOH, (Rogerson).
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2020-07-09 6:07:34 PM
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