Page 64 - 《广西植物》2020年第10期
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10 期 陆昭岑等: 苦苣苔科凹柱苣苔属在越南的发现及水晶凹柱苣苔的补充描述 1 4 4 7
divided nearly to the baseꎬ orbicular ̄ovate. Stamens 2ꎬ diameter. Fruit 4-5 mm longꎬ narrowly ovoidꎬ glabrousꎬ
staminodes 3. Disc annularꎬ ovary ovoid ̄ellipsoidꎬ 1 ̄ dehiscing into 4 valves. Seeds ovoidꎬ obliquely
loculedꎻ placentae 2ꎬ parietalꎬ intrusiveꎬ bifid. Stigma reticulate with raised testa cell wallsꎬ 0.3 × 0.1 mm.
crateriform or disciform. Fruit narrowly ovoidꎬ glabrousꎬ Distribution and habitat: So farꎬ only two
dehiscing into 4 valves. Seeds reticulateꎬ with raised localities have been recorded for the Litostigma
testa cell walls. Only two species in the genus Litostigma crystallinumꎬ one is in Tianbao Townꎬ Malipo Countyꎬ
at presentꎬ L. coriaceifolium is endemic to southwestern Yunnan Provinceꎬ Chinaꎬ and the other closed to Yunnan
Guizhouꎬ Chinaꎬ and L. crystallinum is endemic to the Province is in Du Gia Communeꎬ Yen Minh Districtꎬ Ha
limestone areas of boundary between northern Vietnam Giang Provinceꎬ Vietnam. L. crystallinum grows on the
and southwestern China. moist rock surface of the entrance of limestone caves at
Litostigma crystallinum Y. M. Shui & W. H. elevation of ca. 850 m a.s.l. in China and on the humid
Chen in Edinb. J. Bot.ꎬ 67 (1): 181. 2010. (Fig. 1) open cliffs of travertine caves at elevation of 500-850 m
Perennial herbꎬ stemless. Rhizome subtereteꎬ 3-5 a.s.l. in Vietnam.
mm longꎬ 2-3 mm in diameter. Leaves 5-14ꎬ basalꎻ Phenology: Flowering from November to December.
leaf blade thickly paperyꎬ ellipticꎬ 4.5-8 cm longꎬ 3-5 Conservation assessment: According to Wei et
cm wideꎬ apex acuteꎬ obtuse to roundedꎬ base broadly al. (2010)ꎬ Litostigma crystallinumꎬ was assessed as
cuneiformꎬ margin entireꎬ slightly revoluteꎬ glabrousꎬ Critically Endangered (CR) [B1ab(v) +C2a(i) +D]
green aboveꎬ greyish green beneathꎻ lateral veins 5-6 based on the single population found in the type locality
on each side of midribꎬ flat adaxially and prominent with steadily declined mature individuals recorded from
abaxiallyꎻ petiole 4-15 cm longꎬ glabrous. Cymes 1-2ꎬ 2002 to 2008. Howeverꎬ with the newly discovered
1 ̄floweredꎻ peduncle 3 - 10 cm longꎬ pubescentꎻ 2 ̄ population having many mature plants in Vietnamꎬ
bracteateꎬ smallꎬ lanceolateꎬ ca. 3 × 0.8 mmꎻ pedicel about 40 km away from the northwestern type localityꎬ
2. 5 - 3 cm longꎬ pubescent. Sepals 5ꎬ lanceolateꎬ and the extent of occurrence of this species more than
2 2
ca. 7 × 2 mmꎬ pubescent outsideꎬ glabrous inside. 100 km but it will be less than 5 000 km . Thusꎬ
Corolla purpleꎬ infundibuliformꎬ 1. 5 - 2. 1 cm longꎬ following the IUCN ( 2019) red list categories and
slightly pubescent outsideꎬ glabrous insideꎻ corolla tube criteriaꎬ we propose the conservation status of L.
0.7-1.2 cm long with short proximal undilated partꎬ 2 cystallinum as Endangered (EN) [B1ab (iiiꎬv)]. At
yellow spots inside the tube under the anthersꎻ adaxial the same timeꎬ we believe that more populations of
lobes 2ꎬ rather oblongꎬ ca. 7 × 6 mmꎬ abaxial lobes 3ꎬ L. crystallinum will be found out at cave mouths in many
oblong or obovateꎬ 7 - 9 × 6 - 7 mm. Stamens 2 in limestone areas between southeastern Yunnanꎬ China
anterior positionꎬ adnate to ca. 3 mm above base of and Ha Giangꎬ Vietnam if field investigations are
corolla tubeꎻ filaments linearꎬ slightly erectꎬ ca. 4 mm extensively conducted there.
longꎻ anthers ellipticꎬ ca. 2 mm longꎬ pilosousꎬ Specimens examined: —VIETNAM. Ha Giang:
coherent adaxially. Staminodes 2ꎬ 1 - 2. 5 mm longꎬ Yen Minhꎬ Du Giaꎬ Giang Chuꎬ 105° 09′ 47″ Eꎬ
glabrousꎬ adnate to 2-3 mm above corolla base. Disc 22°56′54″ Nꎬ alt. 540 mꎬ 15 November 2004ꎬ Ching ̄I
annular. Pistil 1.2-1.5 cm longꎻ ovary ovoidellipsoidꎬ Peng et al. 20212 (HAST 111912!)ꎻ Yen Minhꎬ Du
ca. 1.5 mm longꎬ ca. 1 mm in diameterꎬ 1 ̄loculed with Giaꎬ 105°10′24″ Eꎬ 22°56′51″ Nꎬ alt. 500-850 mꎬ
2 parietal and intrusive placentaeꎻ style 9. 5 - 13 mm 28 November 2004ꎬ S. K. Wu et al. WP738
longꎬ pubescent. Stigma disciformꎬ ca. 0. 5 mm in (MO 04825175!).