Page 8 - 《广西植物》2022年第10期
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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.