Corresponding author: Saroj Ruchisansakun (
Academic editor: Y. Mutafchiev
Ruchisansakun S, Suksathan P (2019)
In Thailand, sixty-one native
Fieldwork was conducted in October 2018. The plants were prepared for making herbarium specimens. Each part of the flower was separately glued on the hard paper and dried separately. All parts were measured and described in line with terminology in
THAILAND. Tak Province, Thasongyang District [
Lithophytic, annual herb, up to 6–30 cm tall. Stem erect, up to 1.2 cm in diam., cylindrical, branched, green, densely pilose with short white hairs. Leaves spirally arranged. Petiole 3–7.5 cm long, ca. 2.5 mm in diam., pale green to green to pink, pilose; with 5–7 pairs of long hairs on petiole, up to 2 mm long, green, sometime with red tips. Lamina 9–20 × 3–7 cm, ovate to elliptic, apex acute, base cuneate, margin shallowly serrate, adaxial green, abaxial pale green, pilose on both sides; lateral veins 10–12 pairs. Inflorescence raceme, axillary, 8–12 florets; peduncle 7–10 mm long, 1.5–2 mm in diam., pale green, densely pilose; rachis 8–20 mm long, ca. 1.5 mm in diam., pale green, densely pilose, hairs shorter than those on peduncle. Flowers ca. 20 × ca. 15 mm, ca 3 mm deep, pinkish white with reddish purple lip. Bracts ca. 1 × 0.5 mm, linear to narrowly lanceolate, apex acute, base cuneate, green, caducous, abaxial densely pilose with white hairs. Pedicel 12–15 mm long, less than 1 mm in diam., pink, densely pilose with white hairs. Lateral sepals 2, 5–6 × 6–7 mm, free, broadly ovate, the apex mucronate, the base truncate, pale pink, abaxially densely pilose with white hairs. Lower sepal 11–13 × 8–10 mm, ca. 14–17 mm deep, broadly navicular to subsaccate, apex acuminate and mucronate, white with green tip, densely pilose to strigose outside with long white hairs, distal part gradually constricted into a curved spur, 14–15 mm long, white to pale pink. Dorsal petal 11–12 × 14–15 mm, broadly ovate to obcordate, cucullate, apex emarginate and mucronate, base cordate, white to pale pink, densely pilose with white hairs, abaxial midvein with a white crescent-shaped crest, 1–1.5 mm high. Lateral united petals 20–24 mm long, free: the upper petals 9–10 × 10–11 mm, broadly oblong, apex truncate, base cuneate, upper outer part white to pale pink, lower inner part dark purple; the lower petals 17–19 × 8–10 mm, oblong, apex truncate, pink to reddish-purple; with a pink auricle at the base, ca 1 mm high. Stamens 5; filaments 4–5 mm long, white; anthers white. Ovary ca 4 mm long, 1.5–2 mm in diam., short fusiform, 5-carpellate, green, glabrous. Fruits, short fusiform capsule, 11–12 mm long, 6–8 mm in diam., subglobose, 5–lobed, green, glabrous. Seeds ca. 20 per fruit, ca. 1.34 mm long, ovoid, brown.
Flowering from Oct. to Nov.; fruiting Oct. from Nov.
The new species is only known from the type locality in Tak Province, Thailand.
Critically Endangered B1ab (i, ii, iii) + 2ab (i, ii, iii). This species is only known from the type locality; the extent of occurrence is estimated to be less than 5 km, where it occurs as a small population (
The new species is named in honor of Dr. Thaya Jenjittikul who encouraged the first author to step in and study this lovely plant family.
The author observed five visitations by bees from the family
Pollen of
Seed of
Stem of
Floral visitation by bee in the locality of
The cross sections of the stem of
We would like to thank Frederic Lens, Larissa Chacon-Doria, Pantamith Ratanakrajang, Pornpimon Tangtorwongsakul, and Weerayuth Laohajinda, for their help with different parts of this work.