Page 8 - 《广西植物》2022年第10期
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1 6 2 6                                广  西  植  物                                         42 卷


                                 Table 1  Spore features of Isoëtes from China

                 Number                Megaspore                              Microspore
    Species        of
               chromosomes  Ornamentation        Size            Ornamentation         Size

    I. hypsophila   2n = 2x = 22  Levigate  290-400 μm (mean = 358 μm)  Echinate  19-25 μm (mean = 22 μm)
    I. shangrilaensis  2n = 2x = 22  Tuberculate ̄rugulate 207.25-273.09 μm (mean=244.71 μm) Echinate ̄cristate  11.21-23.66 μm (mean=19.41 μm)
    I. yunguiensis   2n = 2x = 22  Cristate ̄reticulate  340-430 μm (mean = 390 μm)  Levigate ̄granulate  20-25 μm (mean = 22 μm)
    I. taiwanensis   2n = 2x = 22  Tuberculate ̄cristate  280-340 μm (mean = 312 μm)  Echinate  20-28 μm (mean = 24 μm)

    I. sinensis   2n = 4x = 44  Cristate  340-450 μm (mean = 409 μm)  Echinate  23-32 μm (mean = 28 μm)
    I. orientalis   2n = 6x = 66  Cristate ̄reticulate  350-460 μm (mean = 420 μm)  Echinate ̄tuberculate  20-38 μm (mean = 34 μm)
    I. baodongii  2n = 2x = 22  Echinate ̄cristate  390-510 μm (mean = 450 μm)  Echinate  22-27 μm (mean = 25 μm)
    I. longpingii  2n = 4x = 44  Tuberculate ̄cristate  310-410 μm (mean = 350 μm)  Echinate  27-30 μm (mean = 29 μm)
    I. xiangfei  2n = 4x = 44  Cristate ̄reticulate  390-450 μm (mean = 430 μm)  Tuberculate  26-28 μm (mean = 27 μm)

     Note:  Cited from Liu et al.(2008). Datas of I. shangrilaensis and I. baodongii are cited from Li et al.(2019) and Lu et al.(2021)ꎬ respectively.


   hemisphere tuberculateꎬ distal hemisphere echinate ̄  ornamentationꎬ and  densely  low ̄tuberculate  ( vs.
   cristate. Microspores: gray en masseꎬ ellipticꎬ vertical  sparsely tuberculate ̄echinate ) microspores ( Fig. 3ꎬ
   axis length 27-30 μm (mean = 29 μmꎬ n = 20)ꎬ surface  Fig. 4ꎬ Table 1).
   echinate. Chromosome numbers 2n = 4x = 44.            Type: — CHINA. Hunan Province: Huaihua Cityꎬ
       Distribution: — Ningxiang Cityꎬ Changsha Cityꎬ  Tongdao  Countyꎬ  26°14′56.82″ Nꎬ  109°50′0.33″ Eꎬ
   Hunan Province.                                   alt. 298 mꎬ December 28ꎬ 2019. Juan Yang Fern08928
       Ecology: — Submerged in a small pondꎻ alt.    (holotype: PE! barcode 02347220ꎻ isotype: NOCC!ꎬ
   131 m.                                            IBSC!).
       Etymology: — The specific epithet “longpingii”    Description: — Plants aquatic. Rhizome corms
   is derived from the name of the late Prof. YUAN   3-lobed. Sporophylls 20-60 in a tuftꎬ widely spreadingꎬ
   Longpingꎬ who devoted his entire life to hybrid rice  white at the baseꎬ green aboveꎬ spirally arrangedꎬ 15-35
   research in Changsha City ( where the species was  cm longꎬ 2-3 mm wideꎬ flattened on the adaxial sideꎬ
   discovered ) and greatly contributed to global food  rounded on the abaxial sideꎬ base flat and alateꎬ
   security and poverty alleviation (Wangꎬ 2021).    peripheral fibrous bundles presentꎬ central intrastelar
       IUCN Red     List category:   — A single      canal 4. Sporangia: basalꎬ oblongꎬ 4. 4 - 5. 0 × 2. 9 -
   population of about 10 individuals is found in only one  3.3 mm. Ligule: oval triangleꎬ 2.5-2.7×1.4-1.6 mm.
   location in Yujia’ ao Villageꎬ Ningxiang Cityꎬ Hunan  Megaspores: white when dryꎬ earthy yellow when wetꎬ
   Province. Isoëtes longpingii is critically endangered  390-450 μm (mean = 430 μmꎬ n = 20) in diameterꎻ
   (CR) [A1aꎻ B2ab(iv)cꎻ C2a(ii)ꎻ D(2)] according    proximal hemisphere cristateꎬ distal hemisphere reticulate.
   to the Red List Categories and Criteria (IUCNꎬ 2022).  Microspores: gray en masseꎬ ellipticꎬ monoleteꎬ vertical
   2.2 Isoëtes xiangfei Y.H. Yanꎬ Y.F. Gu & J.P. Shu  axis 26 - 28 μm ( mean = 27 μmꎬ n = 20)ꎬ surface
   (Fig. 2ꎬ Fig. 4: A-D)                             echinate. Chromosome numbers 2n=4x=44.
       Diagnosis: — Isoëtes xiangfei is a tetraploidꎬ    Distribution: — Tongdao and Huitong countiesꎬ
   morphologically similar to the diploid I. yunguiensis and  Huaihua Cityꎬ Hunan Province.
   the tetraploid I. sinensis in megaspore ornamentationꎬ  Ecology: — Wetlands and small gulliesꎻ alt.
   but differs in its less reticulateꎬ lower megaspore  298 m.
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