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!).
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