Peliosanthes mantegazziana Pampanini 1906

Peliosanthes mantegazziana (Pamp.) Pampanini (1906: 138) (Figs 1–4) Basionym: — Peliosanthes teta var. mantegazziana Pampanini (1904: 151). Pampanini (1905: 50, Fig. 11). Type: — [MALAYSIA. Penang State: Penang Island,] flowered in the Botanical Gardens of Florence from the seeds originated from Penang and donated by Prof. Paolo Mantegazza in 1901, February 1904, s.coll., s.n. (holotype FI FI-HCI-00046054!). Heterotypic synonym: Peliosanthes graminea Ridley (1911: 207), syn. nov. Type: —[THAILAND.] Tongkah [Phuket Province]: [Phuket Island], abundant on Gunong Toxai [possibly, Ton Sai in Khao Phra Thaeo Wildlife Sanctuary] which is close to the town of Phuket, s.d., C. Curtis s.n. (holotype SING SING0055481!). Description:—Plant herbaceous, terrestrial, perennial, rhizomatous, evergreen, entirely glabrous (except for roots). Rhizome prostrate and often slightly elevated above ground by roots, with short internodes, abundantly branched, up to 6 cm long, up to 12 mm in diameter, brown, bearing roots, cataphylls, foliage leaves and 1–8 inflorescences. Roots numerous, poorly branched, ca. 1–2(4) mm in diameter, rigid, brown to yellowish white, densely covered with root hairs when young. Cataphylls chartaceous, lanceolate to elliptic, up to 6 cm long, ca. 1–1.5 cm wide at base, light brown, soon becoming dry, with green and rigid median portion 2–5 mm wide. Foliage leaves suberect, simple, stiff. Petiole adaxially flattened, (5) 10–20 cm long, ca. 1–2 mm in diameter at middle. Leaf blade entire, linear to narrowly lanceolate (or ensiform), 18–35.5 cm long, 6.5–20(28) mm wide, 13–30 times as long as wide, light to dark green; base narrowly cuneate to decurrent onto petiole; apex attenuate; margin entire; longitudinal veins 3–5(9) (including midvein, showing basal perfect acrodromous venation), parallel, raised on both sides; transversal veinlets numerous, faintly visible, sub-perpendicular to longitudinal veins. Inflorescence a thyrse, with 1–5-flowered cyme in axil of each primary bract, erect to ascending, up to ca. 30 cm long, distinctly shorter than leaves. Peduncle erect, ca. 10 cm long, ca. 1.5–2.8 mm in diameter, usually longitudinally ribbed, green, bearing 2–4 sterile bracts. Sterile bracts lanceolate, navicular, appressed to peduncle or spreading, 13–20 mm long, 1.7–5.3 mm wide at base, light green, scarious along margin, indistinctly unicostate. Rachis straight or slightly flexuose, (13) 15–23 cm long, usually moderately ribbed longitudinally, light green, bearing up to 100 flowers. Primary bracts of thyrse lanceolate, arcuate, slightly navicular, more or less erect, light green, scarious along margin, indistinctly unicostate, proximal ones 11–13 mm long, up to 4.5 mm wide at base, gradually becoming smaller towards inflorescence apex; bracts within cymes similar to primary bracts but up to 3 mm long. Flowers actinomorphic, bisexual, facing more or less upwards and becoming horizontal at late anthesis. Pedicel ascending, straight, 3–6 mm long, ca. 0.5 mm in diameter, with articulation at middle, light green. Perianth widely opening, rotate, homochlamydeous, ca. 6.5–9.5 mm in diameter; tepals 6, apparently free, arranged apparently in two whorls with imbricate-alternate aestivation (in bud), at anthesis basally overlapping by their margins, subequal, broadly triangular-ovate, with more or less rounded or obtuse apex, ca. 2–3 mm long, 1.4–3.5 mm wide, with entire margin, horizontally spreading, light green. Stamens 6; filaments united forming fleshy coronalike structure (so-called corona); corona broadly attached at the level of junction of ovary and tepals, ca. 0.3–0.7 mm high, 3–4 mm in diameter, protruding horizontally towards centre and hanging over the ovary roof, slightly elevated above the tepal bases, with upper surface flat or indistinctly convex, obscurely hexagonal in outline, entirely light green, or green with blue or purple tint (ranging from slight to prevailing one), tint mostly in form of radial streaks; orifice of corona rounded triangular (with angles in the radii of outer tepals), ca. 1 mm in diameter; anthers in the radii of tepals, attached to the inner surface of corona just below orifice, dorsifixed, introrse, sessile, broadly ovate (with thecae diverging at base), ca. 0.3 mm long and wide, light yellow, longitudinally dehiscent. Ovary inferior, broadly obconical, with roof weakly to pronouncedly concave, ca. 2.5 mm high, ca. 3(–4) mm wide in upper part, light green, 3-locular, each locule containing 2–4 ovules; style slightly conical (almost cylindrical), with prominent furrows along borders between carpels, ca. 0.7–0.9 mm high, ca. 0.6–0.8 mm wide at base, reaching the level of anthers, light green; stigmas 3, indistinct, minute, carinal, occupying apical surface of style. Fruit with shriveled pericarp exposing azure blue seeds. Etymology: —The species is named after Prof. Paolo Mantegazza, who provided the seeds (collected by his son) from which the material used for the protologue preparation was grown. Additional specimens examined:— THAILAND. Phuket Province: under the forest canopy, 2012, Shirokov 1201, the herbarium specimen prepared from the living cultivated plant (garden number: 2016.11401) on 6 March 2025, I.A. Kroupsky, M.S. Romanov & V.G. Drokina KRO114 (MW MW1048029); Phuket Province: Rang Yai Island, lowland evergreen broad-leaved forest near sea coast, 22 December 2015, L. M. Osinovetz s.n., the herbarium specimen prepared from the living cultivated plant (garden number: 1649) in March 2016, L. M. Osinovetz & L.V. Averyanov s.n. (LE LE01048474, photos LE01058031) with additional alcohol-preserved specimen prepared in October 2020, L.V. Averyanov, D.D. Sokoloff & M.S. Nuraliev s.n. (photos LE LE01058031); same gathering, the herbarium specimen prepared from the living cultivated plant (garden number: 2019.14669) on 6 March 2025, I.A. Kroupsky, M.S. Romanov & V.G. Drokina KRO115 (MW MW1048030); Krabi Province: Mueang Krabi District, vicinities of Railay Beach, in the forest near trail in Princess Lagoon, 8.005461°N 98.841560°E, likely January or February 2017, A. Volkov s.n., the herbarium specimen prepared from the living cultivated plant (garden number: 2017.14108) on 6 March 2025, I.A. Kroupsky, M.S. Romanov & V.G. Drokina KRO116 (MW MW1048031). Phenology: —The time of flowering in the natural habitats is unknown: the only flowering record made for Peliosanthes mantegazziana in situ is the type collection of P. graminea, for which the collection date has not been preserved. Under the greenhouse conditions, the flowering was documented from September to March. Distribution and ecology: — Peliosanthes mantegazziana is endemic to the west coast of the Malay Peninsula. It is known from Thailand (Phuket Province: Phuket Island and Rang Yai Island, Krabi Province: Railay Peninsula) and Malaysia (Penang State: Penang Island). The species inhabits evergreen broad-leaved forests at elevations below 850 m a.s.l.