Disporum nanchuanense X.X.Zhu & S.R.Yi
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|Disporum nanchuanense X.X.Zhu & S.R.Yi|
CHINA. Chongqing: Nanchuan District, Jinfo Mountain National Nature Reserve, 29°02.67'N, 107°11.32'E, 1386 m a.s.l., 30 March 2018, X.X.Zhu ZXX18025 (holotype: CSH [CSH 0151769!]; isotypes CSH!, KUN!).
Disporum nanchuanense X.X.Zhu & S.R.Yi is similar to D. longistylum ( Léveillé & Vaniot) Hara and D. megalanthum Wang & Tang, but it differs from D. longistylum in its stem which is usually simple, rarely branched, tepals white with purple, apex obtuse, 22-25 × 2.8-4 mm, filaments 20-24 mm long, anthers 5.2-5.6 mm long and ovary ca. 4.6 mm long, style 27-29 mm long; and it differs from D. megalanthum in its inflorescences terminal, petiole 3-13 mm long, tepals white with purple, oblanceolate, apex obtuse, stamens distinctly exserted and ovary ca. 4.6 mm long, style 27-29 mm long, distinctly exserted. Detailed morphological comparison is shown in Table 1 and Figure 4View Figure 4.
Perennial herb with short rhizomes; occasionally with stolons. Roots densely tufted, fleshy. Stem usually simple, rarely branched, 20-45 cm high, proximally with several sheaths. Leaves alternate, concentrated in distal part of stem; petiole 3-13 mm long; blade ovate-lanceolate to oblong, papery to thinly leathery, 6.5-12.5 × 1.1-6 cm, apex shortly acuminate to acute, base broadly cuneate or roundish, glabrous, 3-5-nerved. Inflorescence terminal, 2-7-flowered, non-pedunculate. Pedicels 10-13 mm long. Flowers narrowly campanulate, nodding; tepals 6, oblanceolate, white with purple, glabrous on both surfaces, minutely papillose on the lower margin, 22-25 × 2.8-4 mm, apex obtuse, base gibbous-spurred; spurs ca. 1.5 mm long. Stamens inserted at the base of tepals, distinctly exserted; filaments glabrous, 20-24 mm long, anthers 5.2-5.6 mm long. Ovary oblong, green, glabrous, ca. 4.6 mm long; style glabrous, 27-29 mm long, distinctly exserted, trifid at the apex, branches 3, densely papillose inside.
Flowering from March to April. No fruiting specimens have been seen.
The specific epithet refers to the type locality, Nanchuan District, Chongqing, China. The Chinese name is given as “南川万寿竹”.
Distribution and habitat.
Disporum nanchuanense is presently known only from the type locality in Jinfo Mountain National Nature Reserve, Nanchuan District, Chongqing. It grows under conifer-broadleaved forest at 1386-1411 m, together with Arisaema bockii Engl. ( Araceae ), Cardamine hygrophila T.Y.Cheo & R.C.Fang ( Brassicaceae ), Cephalotaxus fortunei Hook. ( Cephalotaxaceae ), Liriodendron chinense (Hemsl.) Sargent. ( Magnoliaceae ), Pinus massoniana Lamb. ( Pinaceae ), Rhododendron coeloneurum Diels ( Ericaceae ), Sanicula orthacantha S.Moore ( Apiaceae ) etc.
IUCN Red List category.
Disporum nanchuanense is known from only one population, with fewer than fifty individuals seen at this site. Therefore, the new species is assigned a preliminary status of Vulnerable (VU D2), according to IUCN Red List criteria, indicating a population with a very restricted area of occupancy (typically less than 20 km2) or number of locations (typically five or fewer).
(Paratypes). CHINA. Chongqing: Nanchuan District, Jinfo Mountain National Nature Reserve, 28 March 2017, S.R.Yi ZXX17109 (CSH!, KUN!).
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