Russula nympharum F. Hampe & Marxm., 2016

Adamčík, Slavomír, Caboň, Miroslav, Eberhardt, Ursula, Saba, Malka, Hampe, Felix, Slovák, Marek, Kleine, Jesko, Marxmüller, Helga, Jančovičová, Soňa, Pfister, Donald H., Khalid, Abdul N., Kolařík, Miroslav, Marhold, Karol & Verbeken, Annemieke, 2016, A molecular analysis reveals hidden species diversity within the current concept of Russula maculata (Russulaceae, Basidiomycota), Phytotaxa 270 (2), pp. 71-88 : 78-82

Russula nympharum F. Hampe & Marxm. , sp. nov. Figs. 4 , 6–15

MycoBank no.: —MB 816289.

Etymology. —The species epithet refers to the collection site (Val des Nymphes) of two of the paratypes one of which was illustrated in Marxmüller (2014).

Holotype (designated here). — SPAIN. Mallorca: Bunyola, associated with Quercus ilex and Arbutus unedo , 15 December 2011, FH11121505 (GENT).

Short diagnosis. —Basidiomata relatively large and with firm, thick context, surface of stipe, pileus and lamellae with yellow-brownish spots, pileus cuticle red or orange and discolouring to cream, taste acrid, spore print yellow, spore ornamentation with low (up to 0.6 μm), amyloid warts often merged or connected by line connections, hymenial cystidia relatively numerous, hyphal terminations in pileipellis near the pileus margin mainly cylindrical, pileocystidia near the pileus margin 6‒12 μm wide (on average wider than 7 μm).

Pileus up to 100 mm broad, fleshy, firm, first hemispherical, then expanded with depressed centre, extreme margin becoming somewhat sulcate with age, cuticle peeling at margin to 1/3 of pileus radius, glabrous, shining, cream with pale rose to pale orange zones or reddish orange to pinkish red or deep red, often paler to cream at centre, mostly more or less covered with small brownish or reddish spots. Lamellae adnate, crowded, more or less furcate towards the stem, slightly anastomosing, fragile, cream, then yellowish, with yellow-brownish spots at age, edge smooth, concolourous or reddish especially towards the pileus margin. Stem cylindrical to slightly clavate with rounded base, firm, surface minutely wrinkled, whitish, staining yellow-brownish to brownish when handled or with age, especially towards the base. Context firm, whitish, staining yellow-brownish to brownish, taste acrid especially in lamellae, smell fruity or like cedar wood, FeSO 4 and Guaiac very weak or negative. Spore print IV d, IV d–e (coded according to Romagnesi 1967).

Spores broadly ellipsoid, (8–)8.6–9.8(–10.8) × (6.5–)6.9–7.6(–7.9) μm, average 9.2 × 7.3 μm, Q=(1.14–)1.16– 1.23(–1.27), average Q=1.19, ornamentation of moderately large and distant: 4–6(–7) amyloid warts in the circle of diameter of 3 μm on spore surface, warts 0.3–0.6 μm high, connected with occasional to frequent short or longer fine line connections [0–3 (–4) line connections in the circle], occasionally fused in short chains or crests [0–3(–4) fusions in the circle], chains and crests often branched, but rarely forming a reticulate structure, isolated warts rare. Suprahilar plage amyloid and very distinct. Basidia (39–)45–55.5(–62) × (9–)10.5–13(–14) μm, average 50.3 × 11.6 μm, 4- spored, clavate, pedicellate; basidiola first cylindrical or ellipsoid, then clavate, ca. 5–10 μm wide. Subhymenium pseudoparenchymatic. Lamellar trama mainly composed of large sphaerocytes. Hymenial cystidia on lamellar sides moderately numerous, 800–1100/mm 2, fusiform or rarely clavate, pedicellate, acute to acute-pointed on tips and with 2–7(–11) μm long appendage, thin–walled, measuring (60–)75–108.5(–140) × (8–)10.5–13.5(–15) μm, average 91.7 × 11.9 μm, contents heteromorphous, mostly granular-crystalline, turning brownish-red to almost black in sulfovanilin. Lamellar edges covered with marginal cells, cheilocystidia and dispersed basidia; marginal cells on lamellar edges not well differentiated, narrower than the basidiola on lamellar sides, mainly narrowly clavate to subcylindrical, often somewhat flexuous or moniliform, with obtuse tips, measuring (15–)20–31.5(–33) × (3–)4–7(–9) μm, average 25.9 × 5.4 μm; cheilocystidia less voluminous than pleurocystidia, clavate or fusiform, pedicellate, mainly with acute tips and usually with 1–5(–10) μm long appendage, thin-walled, measuring (37–)47–79(–102) × (7–)8–10.5(–12) μm, average 63.1 × 9.3 μm, contents similar as in pleurocystidia. Pileipellis orthochromatic in Cresyl blue, 140– 250 μm deep, not sharply delimited from the underlying spherocytes of the context; vaguely divided in a 70–120 μm deep, strongly gelatinized suprapellis composed of dense, ascending or erect hyphal ends (trichoderm type) and protruding and near surface repent pileocystidia, sometimes covered with an additional, up to 40 μm deep transparent, gelatinous matter that does not colour in Congo red; and a 70–165 μm deep subpellis of less gelatinized, dense, strongly intricate, horizontally oriented, often branched, 2–5(–7) μm wide hyphae. Acidoresistant incrustations absent. Hyphal terminations in pileipellis near the pileus margin with gelatinous coating (not an acidoresistant incrustation) dissolving in KOH, but visible as a hyaline hue in Congo red, terminal cells very variable in size, some very short and comparatively shorter than subterminal cells, mainly cylindrical, sometimes attenuated towards apices, often flexuous, partly moniliform, measuring (10.5–)17.5–30.5(–44) × (2–)2.5–3.5(–4.5) μm, average 20.1 × 2.8 μm; subterminal cells branched or not, often with lateral branches or nodules, more or less equally wide as terminal cells. Pileipellis near the pileus centre composed of hyphal terminations of one or two cells arising from a dense pseudoparenchymatic subpellis layer, terminal cells not very conspicuous among very numerous pileocystidia and sometimes completely suppressed, cylindrical or occasionally subulate, often flexuous-moniliform, measuring (11–)16.5–32.5(–44) × (2–)2.5–3.5(–4.5) μm, average 24.5 × 2.8 μm. Pileocystidia near the pileus margin numerous and often very voluminous, narrowly to broadly clavate or fusiform, mainly one-celled, occasionally two or three celled, rarely with more cells, thin-walled or occasionally with slightly (up to 0.5 μm) thickened walls, obtuse to subacute, usually inflated near apical part, with terminal cells measuring (26–)41.5–94.5(–132) × (4–)6–11.5(–15.5) μm, average 68.1 × 8.8 μm, contents in Congo red heteromorphous, usually granulose, but sometimes partly crystalline or banded, in sulfovanilin turning dark brownish to blackish. Pileocystidia near the pileus centre very abundant, often clustered and in some spots completely replacing the undifferentiated hyphal terminations, very variable in shape and size, partly narrow and cylindrical, partly similar to those near the pileus margin (clavate or fusiform), but usually smaller, often flexuous and occasionally moniliform, terminal cells measuring (18–)28.5–77(–119) × (3–)4.5–8.5(–10.5) μm, average 52.9 × 6.5 μm, contents similar to those near the pileus margin, but often with additional yellowish pigments visible in KOH or water. Cystidioid hyphae with heteromorphous contents in subpellis occasional and in the pileus trama dispersed. Clamp connections absent in all parts.

Examined material. — BELGIUM. Forêt de Soignes, 31 August 2000, H.J. Beker HJB10019 (STU); FRANCE. Drôme Dept.: Gigors, les Chaux, 5 July 1997, H. Marxmüller R-9702 (M); La Garde-Adhémar, Val des Nymphes, Quercus ilex , 30 September 2008, H. Marxmüller R-0898 (M); SPAIN. Mallorca island: Bunyola, Quercus ilex , Arbutus unedo , 15 December 2011, F. Hampe & J. Kleine RUS11121505 (GENT, holotype).

Figures

FIGURES 2–5. Field appearance of three Russula species included in this study. 2. R. maculata (GENT 2011 BT 005). 3. R. maculata (GENT 2010 BT 184). 4. Holotype of R. nympharum (GENT RUS11121505). 5. Russula sp. (LAH MAM 0077). Scale bar equals 30 mm, but only 10 mm for Russula sp. Photos by: F. Hampe (Figs. 2–4) and M. Saba (Fig. 5).

FIGURES 6–9. Russula nympharum (holotype). 6. Pileocystidia near the pileus centre. 7. Pileocystidia near the pileus margin. 8. Hyphal terminations in the pileus centre. 9. Hyphal terminations near the pileus margin. Contents of cystidia are represented as observed in Congo Red for some elements only, the others are simply filled with dots to indicate their cystidial nature. Scale bar equals 10 μm. Drawings by: S. Jančovičová.

FIGURES 10–15. Russula nympharum (holotype). 10. Basidia. 11. Basidiola. 12. Cheilocystidia. 13. Marginal cells. 14. Basidiospores in Melzer’s reagent. 15. Pleurocystidia. Contents of cystidia are represented as observed in Congo red. Scale bar equals 10 μm, but only 5 μm for spores. Drawings by: S. Jančovičová.