Stemona hirtella W.J.de Wilde & Duyfjes, 2019

Wilde, W. J. J. O. de & Duyfjes, B. E. E., 2019, Three new species of Lythraceae and one new species of Stemonaceae described from Indochina, Blumea 64 (2), pp. 177-182 : 180-182

Stemona hirtella W.J.de Wilde & Duyfjes , sp. nov. — Fig. 3

In the key to the species from Thailand ( Duyfjes & Inthachub 2011) or China ( Zhanhe & Duyfjes 2000), this new species keys out next to Stemona kerrii Craib because it is hairy on many parts. Stemona kerrii is a twiner and differs further in various details,among which peduncled inflorescences.Diagnostic features for Stemona hirtella are its 1) hairiness; 2) erect habit; 3) sessile, non-peduncled inflorescences;4) small flowers; 5) thecal appendages present; and 6) the squamulose-rugose abaxial side of stamens. — Type: Mai Van Xing & N.H.Quang MVX 277 (holo L; iso CPNP,F,HN,all n.v.), Vietnam, Ninh Binh Prov., No Quan Distr., Cuc Phuong National Park, N20°17'67" E105°40'16", Cite No. CP1136, 26 Mai 2004.

Etymology. The specific epithet hirtella (Latin, hirtus = hairy.With smallish hairs) refers to the finely hairiness of the plant.

Erect, little-branched herb 30–40 cm tall (known from one col- lection only), very finely hairy almost all over, except adaxial lamina, hairs c. 0.1 mm long. Leaves alternate; petiole 3.5–7.5 cm long; lamina ovate, 11–16 by 5.5–9 cm, base cordate, apex acute-acuminate; 9 –13-veined. Inflorescences axillary, 1–4-flowered, sessile (peduncle absent); bracts c. 5 mm long. Flowers: pedicel 12–16 mm long; tepals narrowly ovate to lanceolate, gradually narrowed into acute apex, 10–11 by (2–) 3 mm, (sparingly) hairy abaxially, glabrous within, margin without hairs; stamens c. 12 mm long, c. 0.8 mm wide, abaxially conspicuously squamulose (bran-like)-rugose, filaments c. 1 mm long, anthers c. 8 mm long, ridge separating the thecae c. 0.5 mm high, petaloid outgrowth of the connective c. 5 mm long, additional appendage c. 1 mm long; ovary minute, c. 1.5 mm long. Fruits and seeds not seen.

Distribution — Vietnam, Cuc Phuong National Park, only known from the type.

Notes — 1. The plant is annotated as being a liana of 60 cm long (but this does not show on the herbarium specimen); the flowers are recorded as violet with light white calyx and the fruits as 8 mm long; additional data about habitat and ecology are not known.

2. The minutely squamulose-rugose surface of the abaxial side of the (dried) stamens is also present in some other species ( Inthachub 2008), e.g., in Stemona kerrii , however, less pronounced.

Acknowledgement We thank the curators of L and P for allowing us to study their collections.The authors are indebted to Dr Sovanmoly Hul of the Muséum national d’Histoire naturelle, Paris, for her kind help and mediation in funding our study in the Paris museum. Jan van Os (L) prepared the beautiful drawings.

Figures

Fig. 3 Stemona hirtella W.J.de Wilde & Duyfjes. a. Portion of flowering stem; b. idem, flowering portion enlarged; c. flower; d. idem, one tepal removed, show- ing 4 stamens, one seen abaxially; e. stamen adaxially, note additional appendage; f. portion of the sqamulose-rugose abaxial surface of stamen; g. detail of hairy lower leaf surface (all: Mai Van Xinh & N.H. Quang MVX_277, L). — Drawn by Jan van Os.