Dendrobium moniliforme var. hongbinii H.B.Yang & B.Q.Zheng, 2024

Dendrobium moniliforme var. hongbinii H.B.Yang & B.Q.Zheng var. nov.

( DzmuDz; FIGURE 1 View FIGURE 1 )

Diagnosis: This new variety is morphologically similar to D. moniliforme . It differs by the length of mentum is more than half of the bud, the angle is obtuse, apex acuminate, the petals and mid-lobe are subelliptic, the ratio of mid-lobe to the labellum is 1/3. (TABLE 2).

Type:— China. Ya’an ( Dzae), Sichuan ( 四ffl): epiphytic on tree trunks in forests, 1200 m, 1th April, 2024, Zheng 002 ( holotype: CAF!).

Epiphytic herb. Stems erect, cylindric, usually 10-20 cm long, 2-3 mm in diam, with many nodes, internodes 2-4 cm long, yellow tinged with dark gray when dry. Leaves several, often alternate on stem above middle, lanceolate, narrowly oblong, 4-5 cm long, 5-10 mm wide, base decurrent into clasping sheaths, apex obtuse and slightly unequally bilobed. Inflorescences 1 to several, borne above middle of deciduous or leafy old stem, usually 1-2-flowered;peduncle 2-3 mm long; bracts dry membranous, pale white, ovate, 3-4 mm long, 2-3 mm wide, apex obtuse; pedicel and ovary slender, 1-2 cm long; flowers white or white lavender-red, aromatic; upper sepals ovate-oblong, 1.3-1.7 cm long, 6-8 mm wide, apex acute, with 5 veins; lateral sepals base oblique and adnate to column foot; mentum conic, apex acute, 8-10 mm long, ca. 6 mm wide. Petals usually slightly wider than sepals, subelliptic, 5 veined, acute; lip white, with yellowish patches, overall outline subelliptic, slightly shorter than sepals, base cuneate; lateral lobes semicircular, erect, embracing column, margin irregularly toothed; mid-lobe elliptic, apex slightly obtuse, entire, glabrous; disk densely pubescent between 2 lateral lobes, base often with an elliptic callus, base of mid-lobe usually with a pale yellow patch; Stamen column white, ca. 3 mm; cap white, conic, apex indehiscent, papillose; stamen column foot base often with purplish red stripes, glabrous.

Flowering period: —April to May.

Distribution and habitat: —Epiphytic on tree trunks in broad-leaved forests, lithophytic on rocks in forests and cliffs in valleys; 1000–1500 m, Central Sichuan Province, China.

Etymology: —The specific epithet refers to Yang Hong-Bin, the discoverer of the variety.

Conservation status:— Only two locations were found to contain the new taxa in Ya’an. Including the type locality, 3- and 2- individuals (ramets) were found, respectively. The two sites were more than 4.0 km apart from each other. To date, the number of mature individuals of the orchid is less than 10, and no further data on its population status have been obtained.