Paphiopedilum charlesworthii var. lannaense W. Tongkham, S. Pumikong, N. Potapohn & W. Bundithya, 2022

Tongkham, Wicharuj, Pumikong, Supalak, Potapohn, Nuttha & Bundithya, Weenun, 2022, Paphiopedilum charlesworthii var. lannaense, a new slipper orchid from Northern Thailand identified by morphological and AFLP analyses, Phytotaxa 531 (1), pp. 1-17 : 16

Paphiopedilum charlesworthii var. lannaense W. Tongkham, S. Pumikong, N. Potapohn & W. Bundithya , ssp. nov

(Figs 7, 8, 9, 10 and 11)

Type:— Thailand: Lampang (ลำปาง) province, Jae Hom (แจ้ห่ ม) district, in lightly shaded or vertical cliffs of limestone at an elevation of 1,100–1,200 m, 23 August 2021, S. Pumikong 021001 (holotype QBG! [no. 132572])

A lithophytic herbs. Leaves 4–5, linear-oblong, slightly obtuse at unequally bilobulate at apex, 2.0– 2.5 cm wide, 10–15 cm long, dark green, purple spotted near base below. Inflorescence 1-flowered; peduncle 9–15 cm long, slender and strong, shortly pubescent, green, densely spotted brownish purple; bract elliptic, obtuse, 1.0 – 1.5 cm wide, 2.5–3.0 cm long, green, spotted dark purple, ciliate. Flower 5.5 – 6.5 cm across; dorsal sepal purplish pink to white with reddish purple veins; synsepal pale yellow - green with reddish brown veins; petals glossy, pale greenish yellow with brown veins; labellum glossy, brownish yellow with reddish brown veins; pedicel and ovary green, pubescent, 3.0 – 3.5 cm long. Dorsal sepal ovate - elliptic to ovate, obtuse, 3.0 – 4.0 cm wide, 4.0 – 4.5 cm long, basal margins slightly recurved, apical margins incurved and undulate. Synsepal oblong - elliptic, subacute to obtuse, 2.0 – 2.5 cm wide, 3.5 – 4.0 cm long. Petals subhorizontal, incurved, narrowly oblong, rounded at apex, 0.8 – 1.0 cm wide, 3.8–4.5cm long, slightly twisted at apex, ciliate at base. Labellum saccate, tapering to narrow apex, 2.0– 2.4 cm wide, 3.0– 3.5 cm long. Staminode obovate - obcordate, obtuse to rarely retuse, 0.9–1.0 cm wide, 0.9–1.0 cm long, rough surface, glittery, yellow with raised yellow wart.

Flowering in cultivation: —July–September

Distribution: —Endemic to Northern Thailand, Lampang province.

Habitat: —Grow on lightly shaded or vertical cliffs on limestone with its roots adhere in cracks or on narrow shelves of limestone.

Etymology: — lannaense describes the name of biggest ancient kingdom (Lanna) in Northern Thailand.

Notes: —This new slipper orchid is morphologically close to Paphiopedilum charlesworthii , from which it differs by its dorsal sepal character, smaller flower size, and its staminode is obovate-obcordate with yellow color, rough surface, glittery and raised yellow wart.