Leucoagaricus brunneorube X. T. Zhu & J. M. Zhang

Zhu, Xue-Tai, Zhang, Jing-Ming, Zhang, Guo-Qing, Fan, Jia-Xin & Dang, Yong-Xiang, 2024, Taxonomic description of a new species of Leucoagaricus and utilization of the Pantone Connect app in classification research, Phytotaxa 642 (1), pp. 84-94 : 88-92

Leucoagaricus brunneorube X. T. Zhu & J. M. Zhang , sp. nov. FIGURE.2–3

Index Fungorum number:—IF901336

Etymology:—The species epithet refers to the pileal surface, which is densely covered with brownish red to maroon furfuraceous squamules, sometimes with purple tinge.

Holotype:— CHINA. GANSU PROVINCE: Northwest Normal University Campus , Alt. 1505m, 6 September 2020, Xue Tai Zhu 4078 (HKAS 128146). GenBank: ITS= OP090324; LSU= OP167978.

Description:— Basidiomata ( FIGURE.2 A–D ) epigeous, stipitate-pileate with lamellate hymenophore, small to medium-sized. Pileus 30–60 mm in diameter, initially globose, then usually hemispherical, finally convex, or irregularly convex; pileal surface felty, background white, densely covered with brownish red to maroon (7629C or 7428C) furfuraceous squamules, sometimes with purple tinge (7428C); margin exceeding lamellae for more than 2 mm in young specimens. Context white, thick, solid, not changing color when cut. Lamellae free, crowded, white, thin, with lamellulae in 1–2 tiers, with entire edge; the edge becomes dark when dry ( Fig.2 F ). Stipe 30–65× 12–20 mm, smooth, cylindrical, usually with big bulbous base, 20–30 mm wide, dirty white, sometimes with pale maroon at the lower part; Annulus simple, located at the upper part of the stipe, white, membranous, thick, upper surface white, lower surface concolor with pileus, or slightly paler; Context white, orange-red in bulb when bruised ( Fig.2 E ). Flavor and odor indistinct.

Basidia 25–35 × 8–12 μm, clavate, 4-spored. Basidiospores [80/4/4], (6.5)6.8–8(8.2) × 4.5–5(5.2) μm, Q = (1.35)1.4–1.65, Q m = 1.53 ± 0.09, ellipsoid to amygdaliform in side view, ellipsoid to obovoid in front view, hyaline, smooth, without germ pore, slightly thickwalled, dextrinoid, metachromatic. Lamella edge sterile, Cheilocystidia densely covered by ash black materials in water, which dissipated immediately in KOH. Cheilocystidia 26–40×10– 15 μm, clavate, hyaline or pale brownish, thin-walled, some with crystals at the apex. Pleurocystidia not observed. Pileipellis a squamule 100–150 μm thick, composed of intricate trichodermal, thin-walled filamentous interwoven hyphal elements, which are hyaline to pale brownish, and frequently incrusted, the terminal cells of which 27–55 × 5–10 μm. Clamp connections not observed.

Habitat and distribution:—Growing solitarily or in small groups in the grove of Cedrus deodara (Roxburgh) G. Don and Syringa oblata Linkl. in the campus.

Additional Specimens examined:— China. Gansu Province: Lanzhou City, Northwest normal university, Atl. 1505m, 16 September 2020, zhang118 (HKAS 128145) ; same locality, 16 September 2020, zhu4078 (HKAS 128147) ; same locality, 18 September 2020, fan02 (HKAS 128148) .

Discussion

Leucoagaricus brunneorube is charactered by the brownish red to maroon pileal surface, thicker pileal context, robust stipe, dark lamellae edge in dried specimens, and the context in bulb turning orange-red when bruised and basidiospores ellipsoid and lack a germ pore, lamella edge sterile, cheilocystidia clavate, some with crystals at the apex, pleurocystidia absent, clamp connections absent in all tissues.

Leucoagaricus brunneorube is morphologically and molecularly similar to La. hesperius , although the latter has a pinkish-reddish brown to orange-brown pileus and lamellae that turn red to almost black under pressure (Vellinga 2010). In terms of molecular resemblance, La. brunneorube is closely related to La. adelphicus and La. pilatianus ( FIGURE. 1 ). However, the latter two species have a plushy-velvety tomentose pileal surface and pale lamellae in dried specimens. La. brunneorube shares morphological similarities with Leucoagaricus cupresseus (Burl.) Boisselet & Guinb. (Vellinga 2010) , characterized by stout stipes, a large bulbous base, thick flesh, and lamellae edges that turn dark brown with age. However, La. cupresseus differs in having a pink-brown pileus, larger basidiomata and spores, and a preference for growing under Callitropsis macrocarpa in coastal areas.

According to Cai (2020), it is estimated that over 90% of fungal species on Earth remain undescribed. Even in university campuses where biologists are actively conducting researches, new species continue to be discovered in recent years. For instance, Xerocomus silwoodensis A.E. Hills, U. Eberhardt & A.F.S. Taylor was found and described in 2007 from the Silwood Park campus at Imperial College, UK (Taylor & Hills et al. 2007).

In the present study, a new species of macrofungi was discovered at Northwest Normal University, located in Lanzhou City in the inland area of northwest China. Lanzhou City is characterized by a strongly continental temperate monsoon climate, and the diversity of macrofungi in this region has been poorly researched in the past. The discovery of the new species La. brunneorube in this area emphasizes the need for increased research efforts to explore the diversity of macrofungi in northwest China.

The coloration of different parts of the macrofungi fruitbody plays a crucial role in taxonomy and classification. The book “Taschenlexikon der Farben” has historically been widely utilized as a tool for describing the colors of macrofungi, aiming to mitigate inconsistencies caused by individual variations, device disparities, and environmental factors in color descriptions ( Hao et al. 2016, Zeng et al. 2017, Qin et al. 2018). However, the lack of reprints for this valuable resource since 1981 has posed challenges for biologists in accessing it. Consequently, there is an urgent need to develop an easily accessible, reliable, and user-friendly alternative tool for accurately describing the color of macrofungi fruitbodies.

The Pantone Connect app has seen widespread adoption across various domains, including artistic design, print media, and sectors related to foodstuffs, environmental elements, and botanical assets ( Martí et al. 2020, Felisberti et al. 2021, Pedersen 2022, Sharma. & Meyer. 2022, Hsu et al. 2022, Ji et al. 2023). Within the specific realm of macrofungi color description, utilizing the Pantone Connect app offers notable advantages.

Firstly, the app provides access to standardized and globally recognized PANTONE colors, providing fungal researchers with a universal, objective, and reliable method of color description.

Secondly, the app enhances the accuracy of fungal color descriptions. Unlike traditional paper-based color charts, which are susceptible to variations due to factors like lighting, ink, and paper quality, the app ensures precise digital representation of colors.

Lastly, the app can be freely downloaded for the Android phone system, facilitating manual color matching by utilizing the color card on the phone even in offline field conditions. Moreover, the app has the capability to import photos and automatically extract the corresponding color codes from them.

Figures

FIGURE 1. ML analysis of Leucoagaricus based on combined ITS and LSU sequence dataset, with Agaricus bisporus as outgroup taxon. Bootstrap values (BP) ≥ 50% from ML analysis and Bayesian posterior probabilities (BPP) ≥ 0.95 are shown at the supported branches. The newly generated sequences are shown in bold.

FIGURE 2. Basidiomata of Leucoagaricus brunneorube (HKAS128146, holotype!). Bars=1 cm.

FIGURE 3. Microscopic structures of Leucoagaricus brunneorube. A: Basidia. B: Pileipellis. C: Cheilocystidia. D: Basidiospores. Bars=10 μm.