Hemileccinum floridanum J.A. Bolin, A.E. Bessette, A.R. Bessette, L.V. Kudzma, A. Farid & J.L. Frank sp. nov.
MycoBank number: MB 840861; Index Fungorum number: IF 840861; Facesoffungi number: FoF 10464;
Pileus 2.8-12.5 cm wide, convex becoming broadly convex to nearly plane in age; surface dry to slightly tacky, smooth to somewhat wrinkled and uneven, glabrous to finely velvety, sometimes with a whitish bloom when young, reddish brown to chestnut brown, cuticle acidic tasting or not distinctive; margin even or nearly so. Hymenophore tubulose 3-12 mm deep, pore surface bright yellow when young, maturing to darker brownish-yellow, not staining when bruised, depressed near the stipe in age, easily detached from the pileus context; pores angular to irregular, 2–3 per mm. Stipe 4-9.5 cm long × 1-3 cm thick, nearly equal or enlarged in either direction, with a pinched base; surface dry, longitudinally striate, nearly glabrous to very weakly scurfy-punctate, not reticulate; whitish overall on young specimens, becoming pale yellow at the apex with variable reddish tints and streaks over a whitish to pale yellow ground color below, with white basal mycelium. Context in the pileus white, slowly staining yellow often from the margin toward the center, with a slight pinkish-red coloration beneath the cuticle; in the stipe, white, slowly staining yellowish from the pileus trama just above the hymenophore partly downward along the exterior stipe trama when exposed. Cuticle stains brownish red or light orange sometimes fading to light green with the application of KOH, olive and then orange or amber with a green ring with NH4OH, and dark orange-amber to orange with FeSO4. The context stains pale orange to yellow then fades with KOH, is negative with NH4OH, and negative or light greyish olive green with FeSO4. Odor slightly sour to not distinctive; taste not distinctive.
Basidiospores olive-brown in fresh deposit, (10–)13–16(–17) × 4.5–6 µm, n = 30, Q = 2.86, elliptical in face view, inequilateral in profile, thin-walled, smooth, lacking an apical pore, grayish yellow in KOH, brownish yellow in Melzer’s. Basidia 32-38 × 8.5-10.5 µm, clavate, 4-sterigmate, sometimes 3- or 2-sterigmate, hyaline in KOH, yellow in Melzer’s, with granular, inamyloid contents. Basidioles 22–29 × 7.5–8.5 µm, clavate, hyaline in KOH, yellow in Melzer’s. Pleurocystidia 25–50 × 6–10 µm, hyaline, ventricose in the middle, ampullaceous at the apex, frequent near the pores. Pileipellis a cutis of loosely interwoven cylindric hyphae with markedly inflated, sphaerocyst-like oval to subglobose terminal cells, 11–33 × 15–22 µm, grayish yellow in KOH, yellow to orange-yellow with granular contents in Melzer’s; hyphae of the pileipellis 4-8.5 µm wide, thin-walled, smooth, grayish yellow in KOH, yellow in Melzer’s. Pileus trama hyphae loosely interwoven, highly variable, 4–16 µm, with rounded terminal ends, thin-walled, smooth, hyaline in KOH, yellow in Melzer’s, inamyloid. Hymenophoral trama boletoid, with lateral elements 5–9 µm, moderately divergent, thin-walled, smooth, hyaline to pale grayish yellow in KOH, pale grayish yellow in Melzer’s. Stipitipellis 4–17 µm wide, hyphae subparallel, highly variable, tubular with rounded ends and granular contents, thin-walled, smooth, hyaline in KOH, yellow-brown in Melzer’s, caulocystidia not observed. Stipe trama interwoven, 9–27 µm, highly variable, tubular with rounded ends, thin-walled, smooth, hyaline in KOH, hyaline to pale yellow in Melzer’s. Clamp connections absent.
Material examined: USA, Florida, Hillsborough County, Violet Cury Nature Preserve, 14 June 2017, A. Farid 625 (USF 301503); University of South Florida Tampa campus, trails near tennis courts in NE corner of campus, 4 Jun 2018, A. Farid 790 (USF 297572), ibid., 30 Oct 2019, A. Farid 1032 (USF 301509). Lake County, Lake Louisa State Park, 4 Sept 2017, J.A. Bolin 142 (holotype USF 301495); Palm Beach County, Frenchman’s Forest Natural Area, Jupiter 7 Nov 20 May 2018, J.A. Bolin 157 (USF 301488), ibid., 7 Nov 2019, J.A. Bolin 142 (USF 301495); ibid., 7 Nov 2019, J.A. Bolin 454 (USF 301491).
Distribution: Solitary, scattered or in groups on the ground with oak; known from Florida, potentially to North Carolina.
Sequence data: ITS: MW675730.1 (ITS1/ITS4); LSU: MW662583.1 (LROR/LR5); EF1a: MW737488.1 (EF1-BF1/EF1-B-R); RPB1: – (RPB1-B-F/RPB1-B-R); RPB2: – (RPB2-B-F1/RPB2-B-R)
Notes: Hemileccinum subglabripes (Peck) R. Halling is very similar, but its stipe is furfuraceous to scabrous or fibrillose and pale to bright yellow. It has smaller narrower spores and smaller sphaerocyst-like elements that measure 10–24 µm. Hemileccinum hortonii (A.H. Sm. & Thiers) M. Kuo & B. Ortiz is also similar, but it has a conspicuously pitted pileus, a smooth to lightly pruinose stipe that sometimes has delicate reticulation on the upper half, and pores that sometimes bruise blue. Hemileccinum rubropunctum (Peck) R. Halling & B. Ortiz has a conspicuously punctate stipe, yellowish context, sometimes with an unpleasant odor reminiscent of stale cigarette butts in an ashtray and larger spores that measure (10) 16–22 × 5.5–7.5 µm. The basidiospores under SEM were smooth, lacking the very minute warts present in some species of Hemileccinum (Šutara 2008, Wu et al. 2014).