Helonias yunnanensis var. mesostyla N.Tanaka, 2019

2b. Helonias yunnanensis var. mesostyla N.Tanaka View in CoL , var. nov. ( Figs. 8 View FIGURE 8 , 9 View FIGURE 9 ).

Differs from var. yunnanensis by the longer style with slightly shorter stigmatic segments, and stamens equaling or slightly exceeding (vs usually shorter than) tepals.

Type:― MYANMAR (BURMA). Myitkyina. Nr. Panwa Pass, alt. 7500 ft, 2 April 1938, Herb 4–5 inches high. Flowers pale blue-purple. Anthers purplish. Older flowers maroon. C.W.D. Kermode 17139 ( Holotype, K-001235138!) .

– Ypsilandra alpina View in CoL auct. non Wang & Tang (1936: 81): Chen (1980: 18) p.p., Chen & Tamura (2000: 87) p.p.

Rhizome (sub)cylindrical, closely annulate with many scars, to 3 cm long, 1.4 cm in diam. Root s filiform, to ca. 2 mm in diam., contractile. Leaves slightly hysteranthous, main fresh rosette leaves 4–7, oblanceolate, to 13. 5 cm long, to 2.2 cm wide, tapering to base, apex apiculate. Flowering stem (4–) 8–12.5 cm long incl. terminal raceme at anthesis, elongating to ca. 41 cm in fruit; peduncle to 11 cm long at anthesis, 33 cm long in fruit; scale-like leaves on peduncle several, becoming smaller and laxer upward, oblong-ovate or lanceolate, acute or acuminate, subherbaceous; inflorescence racemose, ovoid-ellipsoid, 2–2.5(–3) cm long, 1.2–1.5 cm in diam., becoming laxer with progression of anthesis due to elongation of rachis; rachis of inflorescence 0.5–1.5(–2.5) cm long at anthesis, to 8 cm long in fruit; pedicels 0.5–2 mm long at anthesis, 1–3.5 mm long in fruit, ebracteate or lowermost sometimes bracteate. Flowers few to many, crateriform-funnelform, 5.5–9 mm across, spreading horizontally or slightly ascending, deliciously fragrant, adichogamous. Tepals narrowly elliptic or narrowly elliptic-oblanceolate, 3.5–5.3(–7.5) mm long, (1.5–)1.8–2(–3) mm wide, subacute to obtuse, 3-veined, pale blue-purple, pale slaty violet, or white. Stamens equaling or slightly exceeding tepals, usually slightly longer than pistil; filaments (3–) 4.5–5.5 mm long; anthers reniform, unilocular, (0.4–) 0.7–0.8 mm long, purplish. Pistil 1, almost equaling or slightly shorter than tepals, (2.5–) 4–4.2 mm long; ovary globose, trilobed, apex concave, 1.5–2.3 mm long, 1.5–2(–3.3) mm across; style terete, (1–) 2–2.5 mm long; stigma trisected, segments oblong, (0.6–) 0.8–1 mm long, recurved. Capsules erect, broadly obpyramidal, tripartite, ca. 3 mm long, 6.5–7.8 mm across, apex depressed in center; lobes ovoid-conic, strongly divergent, apex obtuse. Seeds many, straw colored, narrowly fusiform, tailed at both ends, 4.2–4.8 mm long, 0.5–0.7 mm wide; body of seed narrowly oblong, 1.5–2.3 mm long, 0.5–0.6 mm wide, brownish.

Additional specimens examined ( paratypes):― CHINA. Yunnan. Gongshan. Cikai. Yipsaka Lake, 3500 m, 12 August 2006, fr., Gaoligongshan Biodiversity Survey 32015 (GH-00292433); Salwin-Kiukiang Divide , Newahlung , 2950 m, 9 July 1936, fr., T.T. Yü 19283 (A, PE-00035447*, PE-00593847*, PE-00593848*); Salwin-Kiuking Divide , Tsukuei , 3850 m, 13 July 1938, fl., T.T. Yü 19337 (PE-00593985) . MYANMAR. Adung Valley, 28°20’N, 97°40’E ( Sources of the Irrawaddy), 8500–9000 ft, 27 May 1931, Kingdon-Ward 9557 (BM-001118041); ibid., 8500 ft, 23 May 1931, Kingdon-Ward 9522 (BM-001118042); Myanmar , opposite to Dazu in Gongshan County of China, 3100–3200 m, 30 July 2013, X.H. Jin et al. ST1434 (PE-02002621*). Distribution:― N Myanmar (border with China), SW China ( NW Yunnan) ( Fig. 15- Ym). Habitat:― Alpine wet meadows and margin of thickets at elevations 2286–3850 m. Conservation status:― This form 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 – May (– July). Ripening:― Usually July – August. Etymology:― The varietal epithet refers to the medium-long style GoogleMaps .

Remarks:―Plants collected by T.T. Yü ( no. 19337, PE-00593985!) on a high peak in NW Yunnan ( 3850 m) appear to be dwarf alpine forms of Helonias yunnanensis var. mesostyla with short leaves (to ca. 4 cm long, 1 cm wide), short flowering stems ( 2.5–4 cm long, including flower-bearing portion), few flowers (4 to 6 per scape), short tepals ( 3.5–4 mm long) and short styles 1–1.5 mm long, obviously reflecting the harsh alpine habitat. These plants may represent the smallest extreme in size within H. yunnanensis var. mesostyla . This variety appears to be closely allied to both H. yunnanensis var. yunnanensis ( Fig. 7 View FIGURE 7 ) and H. alpina ( Fig. 10 View FIGURE 10 ). It differs from H. yunnanensis var. yunnanensis by the longer style and usually slightly shorter stigmatic segments ( Fig. 9A–C View FIGURE 9 , Table 6). The anthers of H. yunnanensis var. mesostyla are usually slightly exserted beyond the tepals ( Figs. 8 View FIGURE 8 , 9A View FIGURE 9 ), while those of H. yunnanensis var. yunnanensis are usually shorter than the tepals ( Fig. 7B, D, E View FIGURE 7 ). Helonias yunnanensis var. mesostyla differs from H. alpina by its shorter, narrowly elliptic or eliptic oblanceolate (vs oblong or oblong-oblanceolate) tepals, and shorter styles and filaments. It is viewed as an intermediate form between H. yunnanensis var. yunnanensis and H. alpina . The geographic range of var. mesostyla (Fig. 15-Ym) partly overlaps with that of H. yunnanensis var. yunnanensis (Fig. 15-Yy) and is close to that of H. alpina (Fig. 15-A). H. yunnanensis var. mesostyla is also close to Helonias jinpingensis , but distinguishable by the slightly shorter, ebracteate pedicels, usually slightly longer style ( Table 6) and vernal flowering.