Cantharellus tricolor Buyck, Randrianjohany & V. Hofstetter
MycoBank: MB 813241 Facesoffungi number: FoF00992
Etymology: the name refers to the three contrasting colours resulting from the brown cap, white stipe and bright yellow hymenophore.
Diagnosis: Differs from C. eucalyptorum in its more bright yellow colour of the hymenophore, particularly when young, and its closer genetic relationship to C. densifolius.
Holotype: MADAGASCAR, Central Highlands, near Ranomafana, collected under E. robusta along the road, 18 February 2006, Buyck & V. Hofstetter 06.247 (PC0085151). Cap mostly 25-45(−60) mm diam., regular or with uneven, waving or undulating lobes, when young with strongly incurved margin becoming even or uplifted when old with a sunken center to strongly infundibiliformous; surface when young mostly entirely cottony-tomentose to pubescent, with age usually disrupting in larger, appressed and concentrically arranged squamules, when wet smooth and sometimes almost velvety, colours varying from coffee-with-milk or the colour of milk chocolate, to more reddish or grayish hazelnut or cinnamon brown (5C3-4, 5B3, 4B2-3). Hymenophore decurrent, of well-developed, gill folds, 2-4(6) mm high, quite thin and often fissured over their entire height, a bright chrome to yellowish orange when young (more intensely yellow than 2- 3A7), forkings not abundant and mostly close to the cap margin, varying from completely smooth to heavily anastomosed in between gills. Stipe mostly and sometimes distinctly shorter than the cap diam., more rarely quite slender and exceeding the cap diam., 8–17 mm diam., up to 30 (04) mm long, subcylindrical or slightly narrowing downwards, mostly white, but sometimes also tinged with chrome yellow or a diluted yellowish to cream over part or all of its surface, except for the extreme base which remains generally pure white, often developing similar squamae as the cap, but lower and solid. Flesh firm and thick beneath the cap center, white but yellowing near the surface or when handled. Taste mild. Smell faint and untypical. Spore print distinctly yellowish. Spores ellipsoid, reniform to almost oblong or even cylindrical, l(7.3)8-8.31-8.7× (4.2)4.5-4.90-5.3(5.4) μm, Q=(1.3)1.5-1.71-1.9(2.1), smooth, filled with one large, oily inclusion. Basidia 50-60(65)×7–9 μm, subcylindrical to weakly clavulate, (4)5-6-spored and with 5–8 μm long sterigmata (longer for 2–3 spored basidia and also rather frequently deformed); basidiola not particularly irregular in form. Subhymenium filamentous, with cells of similar diam. as the basidium base. Cystidia none, however some specimens are completely sterile forming aborted basidia, resembling very irregular, cystidia-like cells in the hymenium. Pileipellis a loose (tricho)cutis of ramifying, thick-walled hyphal extremities, densely septate with up to 10 consecutive cells, sparsely branching, measuring mostly 4-6(9) μm diam. toward the cap margin often somewhat wider, terminal cells generally subcylindrical and regular, sometimes locally inflated or subapically constricted; pigment inclusions very apparent inside cells, strongly refringent. Clamp connections absent from all tissues.
Material examined: MADAGASCAR, Central Highlands, 24 km before reaching Antananarivo when returning from Andasibe, bought from vendors along the RN2 before reaching the village of Ambanitsena, 28 February 2000, Buyck 00.1827 (PC0085149); ibid., collected in Eucalypt plantations on lateritic soil, 4 February 2006, Buyck & V. Hofstetter 06.147 (PC0084110), ibid., 7 February 2000, Buyck & V. Hofstetter 06.179 (PC0084129), 06.180 (PC0084130), 06.219 (PC0084827); near Ranomafana, collected under E. robusta 18 February 2006, Buyck & V. Hofstetter 06.247 (PC0085151); near Antananarivo, along RN7 direction Antsirabe, bought from vendors, 25 January 2008, Buyck & V. Hofstetter 08.159 (PC0085148), 08.163 (PC0085150); near Ambila Lemaitso, in littoral forest with Uapaca littoralis, Sarcolaena and Leptolaena spp. and Asteropeia multiflora on deep sandy soil, 29 June 2011, Buyck & V. Hofstetter 11.041(PC0085572).
Notes: This chanterelle is clearly a cryptic species that cannot be unequivocally distinguished from its twin C. eucalyptorum with morphological features unless specimens with very typical colour are compared. Under the microscope, C. tricolor has usually somewhat more densely septate hyphal extremities, as well as overall shorter basidia compared to C. eucalyptorum, but with more collections such differences may not hold up. Notwithstanding the morphological similarities, our phylogeny (Fig. 135) reveals that both species are not sister to each other, and that each one is more closely related to a different African mainland chanterelle: viz. the African C. tanzanicus is sister to C. eucalyptorum, whereas C. tricolor is closer to the African C. densifolius and the Malagasy C. albidolutescens as well as to another, still undescribed Malagasy chanterelle, both of which have a much paler, practically white hymenophore. The two chanterelles grow side by side in exactly the same localities and are sold in mixtures, often after having been washed, which makes both species even more alike. On several occasions, we have tried without success to sort all specimens to the correct species when buying mixtures from merchants. We have observed this species also once in endemic vegetation, growing in the deep sandy soils of the littoral forest where we noted Uapaca littoralis, various Sarcolaena and Leptolaena spp. as well as Asteropeia multiflora as possible host trees. Nevertheless, we would not dare, in retrospect, to confirm with absolute certainty the complete absence of any Eucalyptus specimen in the surroundings. This east coast collection had a much paler cap than usual, also a more slender stipe, but shared the intensely yellow gill folds. Spore measurements of other collections of this species revealed a greater variability than for the other species here described: 00.1827/ (8.1)8.5-9.14-9.8 (10.4)×(4.2)4.5-4.86-5.2(5.4) μm, Q=(1.6)1.7-1.89-2.1(2.3) Holotype/ 06.246 (7.3)8-8.31-8.7×(4.2)4.5-4.90-5.3(5.4) μm, Q=(1.3)1.5-1.71-1.9(2.1) 06.180/ (6.9)7.4-7.85-8.3(8.5)× (4.2)4.6-4.98-5.4(5.6) μm, Q=(1.3)1.4-1.59-1.7(2)