Plant of the month January,2020
Eng (thai)

 

 

Didymocarpus formosus Nangngam & D.J.Middleton, Thai Forest Bull., Bot. 42: 37 (2014).
Gesneriaceae

Description: Epilithic herb, sparsely or densely multicellular hairs on stem, veins beneath, petioles and inflorescences. Leaves 3-4 pair, opposite-decussate, anisophyllous; ovate, 7–19 cm long; apex acuminate; base obliquely cordate; margin serrate; secondary veins 6–8 on each side; petioles to ca 12 cm long. Inflorescences solitary, terminal, cymose, to ca 14 cm long, peduncles to ca 12 cm long; flowers red-maroon, pendulous; pedicels 2–3 mm long; bracts 2, opposite, purple, orbicular, ca 7 mm, caducous. Calyx pinkish purple, broad campanulate, 5-lobed; tube ca 1.3 cm long; lobes broad triangular, ca 2 mm wide. Corolla funnelform, ca 6 cm long; tube ca 4 cm long, widening at ca 3 cm above, pinkish purple toward base; lower lip 3-lobed, orbicular, ca 1 cm; upper lip 2-lobed, broad elliptic, ca 8 mm. Fertile stamens 2, inserted at ca 3.5cm above the base of the corolla; filaments ca 1 cm long; anthers oblong, ca 4 mm, white-bearded; staminodes 3, filaments 2–3mm long. Disc cylindric, 2 mm long, margin irregularly lobed. Ovary cylindric, ca 5 cm long, sparsely indumentum; style glabrous; stigma capitate. Capsules unknown.

 

Distribution: Endemic to Thailand, only recorded from Doi Phu Kha National Park, Nan Province, on rocks surfaces, shaded by streams, montane forest, ca 1,300 m.

Thai name: สร้อยเมืองน่าน (Soi Muang nan)

Photos: Preecha Karaket (Doi Phu Kha, Nan)

References: 
Nangngam, P. & Middleton, D.J. (2014).  Five new species of Didymocarpus (Gesneriaceae) from Thailand. Thai Forest Bulletin (Botany) 42: 37.