Thismia, Griffith, 1845

Nuraliev, Maxim S., Yudina, Sophia V., Truong, Ba Vuong, Do, Thi Xuyen, Luu, Hong Truong, Kuznetsov, Andrey N. & Kuznetsova, Svetlana P., 2020, A revision of the family Thismiaceae (Dioscoreales) in Cambodia, Laos and Vietnam, Phytotaxa 441 (3), pp. 229-250 : 240-242

Thismia . nigricoronata Kumar & S.W.Gale in Kumar et al. (2017: 234 , Fig. 4 , 5 )

TYPE: — LAOS. Vientiane Province: Vang Vieng District, Nam Pae Village, elevation 544 m, 28 April 2012, S. W. Gale, P. Kumar, P. Santainsy, P. Phunthavong HNL-KFBG 0099 (holotype: HNL, spirit).

Description

Plant generally glabrous. Roots vermiform. Leaves scattered, up to 7.5 mm long. Pedicel ca. 2 mm long. Flower terminal and solitary, actinomorphic, 25–40 mm long, 7–7.5 mm wide. Hypanthium ca. 4.5 mm long, narrower towards base (ca. 4.5 mm in diam.), wider above (ca. 5.5 mm in diam.); outer surface white tinged yellow-green, densely covered with longitudinally arranged irregularly sized verrucae, with 12 depressed green ribs; inner surface smooth (without transverse bars), with a protruding ring-like structure just below the stigma.Annulus with shape of a vertically elongated dome, 3.5–4 mm long, ca. 5.5 mm in diam. at base, bright yellow-green with 6 dark green longitudinal ribs, outside covered with densely arranged papillae except on the ribs and inside smooth, with orifice ca. 2.7 mm in diam. Outer tepals triangular, gradually tapering, reflexed, white, translucent, 2.5–3 mm long, ca. 1 mm wide at base. Inner tepals obliquely spatulate, black, rough and irregularly carbunculate, distally broadly fused in a contorted aestivation to form a crown-like mitre with an aperture in the centre, basally ca. 1 mm wide, broadened towards the mitre to ca. 4 mm wide. Each tepal bearing a flagellate appendage close to the mitre aperture; appendages erect, black and carbunculate towards base and translucent white and smooth towards apex, 7.2–17.7 mm long, ca. 0.8 mm wide towards base and abruptly narrowed towards apex to less than 0.2 mm wide. Stamens quadrangular, 4.8–5.5 mm long, 0.7–0.9 mm wide, with long supraconnectives, fused laterally along their entire length except for the filaments and the rounded apices to form a stamen tube. Supraconnectives with the apical 1/3 bent at 90° towards the hypanthium, sparsely covered with multicellular hairs, without appendages. Thecae adaxial (facing the hypanthium), separate, surrounded by sparse glandular trichomes. Interstaminal glands absent. Ovary obconic, with outer surface longitudinally verrucose, ca. 3.5 mm long. Stylar column cylindrical, ca. 0.75 mm long, ca. 0.7 mm wide; styles fused together forming a dome-like structure ca. 1 mm long and wide.

Etymology: —The specific epithet “ nigricoronata ” refers to the black and crown-like mitre characteristic of this species.

Phenology: —Flowering in April.

Distribution: —Endemic to Laos, Vang Vieng area. Only known from the type collection.

Figures

FIGURE 4..Thismia mucronata. A, B. Inflorescence, lateral and oblique views. C. Mitre, oblique view. D, E. Young fruit (soon after hypanthium abscission), apical and lateral views. F, G. Excavated root system showing root suckers. All photos by M. Nuraliev from Nuraliev 1009.

FIGURE 5..Thismia puberula. A–C. Lateral views of flowers showing variation of flower shape. D, E. Mitre, oblique and apical views. F. Perianth, showing inner surface of mitre. All photos by M. Nuraliev from Yudina et al. 15.