Helonias parviflora (F.T.Wang & Tang) N.Tanaka, 2019

Tanaka, Noriyuki, 2019, Taxonomy, evolution and phylogeography of the genus Helonias (Melanthiaceae) revisited, Phytotaxa 390 (1), pp. 448-450 : 448-450

5. Helonias parviflora (F.T.Wang & Tang) N.Tanaka , comb. nov. ( Figs. 11 , 12 ).

≡ Ypsilandra parviflora Wang & Tang (1943: 106) . Type (lectotype, designated here):― CHINA. Kouy-Tcheou [Guizhou], Lou-tsongkouan , 1450 m, Avril 1910, J. Esquirol 2013 (non 3012) (P-00730552*!). Isolectotype: E-00115519!, K-000400239 *!

– Ypsilandra cavaleriei auct. non H. Lév. & Vaniot: Chen (1980: 17), p.p.; Chen & Tamura (2000: 87), p.p.; Tanaka (1997c: 222; 1997d: 286; 1997e: 329; 1998a: 106), p.p., as to J. Esquirol 2013 (E-00115519!).

Description:―Rhizome cylindrical, to 1.5 cm long, 1.2 cm in diam. Roots filiform, to 2 mm in diam., white, contractile. Leaves slightly hysteranthous (vs. flowering in same year), main fresh rosette leaves usually 7–11, narrowly oblanceolate, to 17 cm long, to 1.8 cm wide, tapering to base, apex acute, with minute apiculus 0.6–1 mm long. Flowering stem terete, 11.5–27 cm long; peduncle ca. 10–25 cm long, scale-like leaves on peduncle narrowly (oblong-)lanceolate or narrowly deltoid, subherbaceous, smaller upward; pedicels 1–3 mm long, the lowermost sometimes bracteate; inflorescence racemose, narrowly ovoid or narrowly cylindrical, ca. 1.5–3 cm long, 1.2–1.5 cm in diam. Flowers 8–22, crateriform or funnelform, 4–7 mm across, facing upward or spreading horizontally, nodding at late anthesis. Tepals 6, narrowly oblong-elliptic or oblong-oblanceolate, 3.8–4.5 mm long, 1.2–1.6 mm wide, 3-veined, white, rose or red. Stamens 6, about equaling tepals; filaments 3–4 mm long; anthers unilocular, reniform, ca. 0.7–0.9 mm long. Pistil 1, 3–3.6 mm long, equaling or slightly shorter than stamens and tepals; ovary globose, 1.4–2 mm long, 1.8–2.3 mm across, trilobed, apex depressed in center; style 1.2–1.5(–2.6) mm long, slightly broadened distally; stigma slightly trilobed, segments ca. 0.1–0.2 mm long, apex slightly depressed in center, 0.6–0.8 mm across. Fruit and seeds not seen.

Additional specimens examined:― CHINA. Guizhou. Lu-Tsoon-Kwan, Kweiyang [Guiyang], 15 April 1936, fl., S.W. Teng 90072 (A, IBK-139442*, PE-00035449*); Kouy-Tcheou [Guizhou], Pinfa, Kouy-yang, 8 Avril 1907, J. Cavalerie 3012 (lectoparatype of Ypsilandra parviflora , P-01724138*) .

Distribution:― China (Guizhou) (Fig. 15-P).

Habitat:―Banks along streams at elevation 1450 m.

Conservation status:―The species is very local and the population size is supposedly small. Preliminarily assessed as DD according to the criteria set out in IUCN (2001).

Flowering:―March–April.

Remarks: Judging from the features of the style and stigma, Helonias parviflora appears to be most closely allied to Ypsilandra cavaleriei ( Léveillé 1905) , which was treated as a form with small flowers of H. thibetica ( Tanaka 1998a: 106) . Helonias parviflora (under the name of Y. parviflora ) was once included in Y. cavaleriei ( Chen 1980, Chen & Tamura 2000), but I recognize it as an independent species, in agreement with Wang & Tang (1943). Helonias parviflora is distinguishable from Y. cavaleriei by its smaller flowers with shorter tepals, stamens and pistils and by its shorter pedicels. In H. parviflora ( Figs. 11 , 12 ), both the pistil and the stamens are nearly as long as or slightly shorter than the tepals (i.e. not exserted beyond the tepals), and the stigma is 0.6–0.8 mm in diameter (S.W. Teng 90072, A) and slightly trilobed. In Y. cavaleriei , both the pistil and the stamens are normally exserted beyond the tepals at and after anthesis, and the stigma is smaller (ca. 0.3–0.45 mm in diameter) and discoid or subcapitate, not obviously trilobed. As far as images are examined, the following two specimens somewhat resemble Helonias parviflora . Details of the flowers (e.g. shape of the stigmas) are, however, unclear. Further closer (direct) examinations are needed to precisely identify the specimens: CHINA. Guangxi. Fong-tung, Yaoshan, elev. 1000–1200 m, 31 March 1930, S.S. Sin 9104 (PE-00035451*!). Hunan. Xuan zhang, B.Q. Zhong 762 (PE-00593851*!).

Figures

FIGURE 11. Helonias parviflora from China (J. Esquirol 2013, isolectotype, E-00115519). A. Habit. B, C. Closeup of inflorescence.

FIGURE 12. Helonias parviflora (S.W. Teng 90072, A). A. Pedicellate flower with frontal tepal and filament removed. B. Pistil. Drawn by Noriyuki Tanaka.