Lactifluus bicapillus Lescroart & De Crop

Crop, Eske De, Lescroart, Jonas, jouonkou, Andre-Ledoux, Lange, Ruben De, Putte, Kobeke Van de & Verbeken, Annemieke, 2019, Lactifluusbicapillus (Russulales, Russulaceae), a new species from the Guineo-Congolian rainforest, MycoKeys 45, pp. 25-39 : 29-32

Lactifluus bicapillus Lescroart & De Crop Figs 2, 3, 4

Diagnosis.

Lactifluus bicapillus differs from L. xerampelinus by its yellowish-orange to dark red cap, fertile lamella edge, a lampropalisade with two types of terminal elements as pileipellis type, and a distribution in the Guineo-Congolian rainforest.

Holotype.

CAMEROON. East Region, Haut-Nyong division, Somalomo subdivision, Dja Biosphere Reserve, alt. ca 640 m, 3°21.83'N, 12°44.18'E, rainforest with Uapaca paludosa and U. guineensis , 14 May 2014, leg.: De Crop & Verbeken, EDC 14-249 (GENT!).

Basidiocarps medium-sized. Pileus 34-79 mm in diameter, firm, infundibuliform to deeply infundibuliform, planoconvex with central depression when younger; margin involute when juvenile, becoming inflexed up to reflexed when older; edge entire, sometimes eroded when older; surface felty to chamois leather-like, often slightly pruinose in the centre, often grooved, concentrically wrinkled, in young specimens completely velutinous and somewhat translucent; rubiginous (7D6-7) in centre, becoming paler and more orange towards the margin (6C5-6 to 5A5-6); young specimens dark reddish or burgundy in centre, to bright orange or yellow at the margin (8F6 to 7B6, to 6A5, 4AG); secondary velum absent. Stipe 16-39 × 6-12 mm, cylindrical to slightly tapering downwards, often laterally curved near the base, central to eccentric insertion to pileus, entire or bruised appearance, sometimes with white flocks near the base; surface smooth and felty, sometimes pruinose, yellowish orange (5AB5-6), becoming slightly paler and more yellow near the base and/or lamellae (5A4-5). Lamellae intervenose, transvenose, sparingly bifurcating; attachment adnate to decurrent with some lamellae forming a small tooth; juveniles not brittle, rather thin, older specimens brittle to very brittle, thick to very broad; edge entire and concolourous; distant, 3-5 + 6-9 L+l/cm, between 2 lamellae often 3 lamellulae, with regular short long-short pattern; creamy yellow (3A2) to yellowish orange (4A4). Context white, with a faint yellow tinge, colour not changing when cut, but in 1 collection (EDC 14-238) becoming brown when damaged, rather solid and full, smell sweet or not distinct, taste mild. Latex white, somewhat astringent, rather abundant, becomes less abundant and more watery with age, mild, colour rarely changing brownish when isolated. Chemical reactions unchanging with Fe2SO4; context faint blue after 5 sec. with guaiac.

Basidiospores [6.2] –7.3–7.9– [9.6](10.3) × [4.6] –5.5–5.9– [6.8] μm; ellipsoid, with Q = (1.22)1.31-1.39(1.51); ornamentation amyloid, composed of low ridges and warts, up to 0.2 μm high, forming an incomplete to complete reticulum; plage inamyloid or centrally amyloid. Basidia 43-62 × 8-12 μm, rather long, narrowly subclavate, 1-, 2- or 4-spored; content oleiferic. Sterile elements abundant, 19.5-40 × 3.5-5.5 μm, not emergent, cylindrical, septate with clamp-like bulges under the septum, with rounded apex. Pleurocystidia absent. Pleuropseudocystidia very scarce in mature specimens, abundant in young specimens, narrowly and irregular cylindrical to flexuose, 3.3-4.6 μm diam., not emerging, apex obtuse, oleiferic content. Lamellae-edge fertile, consisting of basidioles with some basidia. Marginal cells absent. Hymenophoral trama cellular, with sphaerocytes and abundant lactifers. Pileipellis a lampropalisade, up to 275 μm thick; terminal elements of two types, without transitional forms: the first type long and slender, thick-walled and often septate, with a wide base, up to 7 μm, and growing thinner towards the apex, down to 1-2 μm, length 52-92 μm, often narrowing rather abruptly, and twisted; the second type short and broad, also thick-walled and often septate, not specifically narrower towards the apex, often twisted, 20-44 × 5-7 μm; subpellis composed of mostly rounded cells. Stipitipellis similar to pileipellis but not as thick; terminal elements of the long type 52-75 × 5-7 μm; terminal elements of the short type 22-29 × 5-7 μm. Clamp-connections absent.

Distribution.

Known from Cameroon and Gabon.

Ecology.

Guineo-Congolian rainforest, scattered on forest floor under Gilbertiodendron dewevrei , Uapaca guineensis , U. acuminata , and U. paludosa .

Etymology.

A combination of ‘bi’ and ‘capillus’, referring to the two types of terminal elements in the pileipellis and stipitipellis.

Conservation status.

Unknown.

Specimens examined.

Cameroon. East Region, Haut-Nyong division, Somalomo subdivision, Koulou village, alt. ca 650 m, 3°23.61'N, 12°44.50'E, rainforest, Gilbertiodendron dewevrei , Uapaca guineensis , U. acuminata , 15 May 2012, De Crop, EDC 12-071 (GENT); East Region, Haut-Nyong division, Lomié subdivision, Bosquet village, alt. ca 610 m, 3°07.82'N, 13°53.36'E, rainforest with many Uapaca trees, on a riverbank, Uapaca guineensis , 24 May 2012, De Crop, EDC 12-169 (GENT); Ibidem, Gilbertiodendron dewevrei , De Crop, EDC 12-174 (GENT); Ibidem, Uapaca guineensis , EDC 12-176 (GENT); East Region, Haut-Nyong division, Somalomo subdivision, Dja Biosphere Reserve, alt. ca 650 m, 3°21.90'N, 12°44.15'E, rainforest, Uapaca paludosa , U. guineensis , 14 May 2014, De Crop & Verbeken, EDC 14-238 (GENT); Ibidem, alt. ca 640 m, 3°21.83'N, 12°44.18'E, De Crop & Verbeken, EDC 14-249 (GENT); Ibidem, alt. ca 650 m, 3°19.87'N, 12°45.42'E, rainforest, near the river, Uapaca sp., 17/05/2014, De Crop & Verbeken, EDC 14-284 (GENT).