Phallus mengsongensis H.L. Li, L. Ye, P.E. Mortimer, J.C. Xu & K.D. Hyde, 2014

Phallus mengsongensis H.L. Li, L. Ye, P.E. Mortimer, J.C. Xu & K.D. Hyde View in CoL , sp. nov. Fig. 2 View FIGURE 2 . C-1, C-2.

MycoBank MB 804689

Type: — CHINA. Yunnan Province: Xishuangbanna, Mengsong Village , UTM-N2379744.485281, UTM-E653217.753714, alt. 1600m, 4 October 2012, Lei Ye ( HKAS 78343 , holotype) .

Basidiocarp egg-shaped at first, elliptical or ovoid, 17–20 mm high × 9–11 mm wide, greyish white or light grey (1B1 or 1C1) with scales, and short white basal rhizomorphs. The egg soon ruptures to reveal a cap and stipe which reaches a height of 94–142 mm at maturity. Indusium absent. Cap 12–28 mm long, 8–18 mm wide, reddish-orange (7A6), narrowly campanulate with a well-developed apical opening ( Fig. 2 View FIGURE 2 . C-1). Cap surface reticulated with strongly protruding ridges and sunken pits; the pits of the gleba containing a sticky, smelly, yellowish-brown (5E4) spore mass, which is carried away by flies and then the reddish-orange (7A6) cap is revealed. Stipe 94–142mm high × 3–5mm wide, uniformly pure white to pale orange (6A3), erect, pliant, and nearly cylindrical or more usually tapering upwards, slender, hollow, the walls being deeply, and multiply lacunose, the elliptical or polygonal lacunae forming a sort of fractal sponge. Volva present, with light brown (6E8) appressed scales on a greyish-white (1B1) background, with short, white, basal rhizomorphs. Basidiospores [100/4/4] 3.5–5 × 1.5–2um, L=4.1, W=1.9, Q=2.15, elongate or cylindrical, smooth and thick walled, hyaline, with oil droplets. Hyphae of cap and stipe 32–50 µm wide, foam-like (not tightly packed), variously shaped, hyaline, and smooth-walled. Hyphae of volva 3–5 µm wide, branched, hyaline, septate, with clamp connections ( Fig. 3 View FIGURE 3 ). Odour of excrement or carrion.

Habitat/Distribution: —gregarious on rotten woods and sticks, Yunnan Province, China.

Etymology: —the species epithet “mengsongensis” refers to the place where the species was collected.

Other material examined:— CHINA. Yunnan Province: Xishuangbanna, Mengsong Village , UTM-N2379744.485281, UTM-E653217.753714, alt. 1600m, 20 September 2012, Lei Ye ( HKAS 78342 , paratype) ; ibid. 16 October 2012, Lei Ye ( HKAS78345 , paratype) ; Ibid. 17 October 2012, Lei Ye ( HKAS78344 , paratype) .

Notes: —The main distinguishing characters of Phallus mengsongensis are a remarkable well-developed opening at the apex of the narrowly campanulate cap ( Fig. 2 View FIGURE 2 . C-1), and the colour of the cap and stipe, which is reddish-orange (7A6) and pale orange (6A3), respectively. The deeply reticulate stipe and scaly volva are also useful in distinguishing the new species from others in the genus. This species morphologically closely resembles P. rubicundus (Bosc) Fr. (1823: 284) , P. calongei G. Moreno & Khalid (2009: 458) , P. drewesii Desjardin & B.A. Perry (2009: 545) , P. minusculus Kreisel & Calonge (2002: 600) , and four varieties of P. costatus which are similar in colour. Immature fruiting bodies of Phallus species grow underground, are roughly spherical to ovoid, and have a soft or gelatinous surface; the mature fruit bodies are bell-shaped with a reticulated cap, single stipe and volva ( Moreno et al. 2009; Desjardin & Perry 2009; Calonge 2002). However, P. mengsongensis , P. rubicundus , P. calongei , P. drewesii , P. minusculus and four varieties of P. costatus have subtle morphological differences ( Table 2 View TABLE 2 & 3 View TABLE 3 ). If we compare P. mengsongensis with P. calongei , the cap of P. calongei sweeps upwards at the margin, the stipe is white without a deeply reticulate pattern made up of elliptical or polygonal segments, and the volva of P. calongei is not scaly ( Moreno et al. 2009). P. drewesii should be compared with P. mengsongensis ; however the cap of P. drewesii is white with an orange tinge under the gleba and is less strongly reticulate than P. mengsongensis ; the apical opening of P. drewesii is perforate and truncated ( Fig. 6. A&B View FIGURE 6 ); and the stipe of P. drewesii is pure white and the spores are pale brown ( Desjardin & Perry 2009). P. minusculus should be compared with P. mengsongensis ; however, the stipe of P. minusculus is white without a deeply reticulate pattern, and the volva is not scaly ( Calonge 2002). P. rubicundus should also be compared with P. mengsongensis ; however, the cap of P. rubicundus is not strongly reticulate, and the top of the cap of P. rubicundus doesn’t have a remarkable well-developed opening. The red stipe of P. rubicundus consists of smaller chambers than P. mengsongensis , and P. rubicundus has a white volva ( Liu et al. 2005) ( Table 2 View TABLE 2 ).

The fruiting body colour of P. mengsongensis closely resembles P. costatus (Penz) Lloyd var. costatus (1909: 10), P. costatus (Penz) Lloyd var. dailingensis (1954: 72) , P. costatus (Penz) Lloyd var. epigaeus (1938: 76) and P. costatus (Penz) Lloyd var. sphaerocephoalus (2002: 123) . However, the fruiting bodies of P. costatus var. costatus are larger and yellow, and contain a plate-like apical opening and light green spores; whereas P. costatus var. dailingensis has a collar-like, outwardly incurved, apical opening, a white partial veil and light green spores. P. costatus var. epigaeus has a large plate-like apical opening with coarse reticulate veins and light olive green spores, whereas P. costatus var. sphaerocephalus has a nearly spherical or peach-like and yellow cap, and outwardly incurved apical opening with reticulate veins on surface and white veil ( Liu et al. 2005) ( Table 3 View TABLE 3 ).