Page 7 - 《广西植物》2022年第10期
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10 期                           舒江平等: 中国水韭属两个四倍体新种                                         1 6 2 5

   environmental conditions (Liu et al.ꎬ 2006ꎻ Cavalheiro ̄  Hillsboroꎬ Oregonꎬ U. S. A.) at 30 kV. Megaspore
   Filho et al.ꎬ 2021ꎻ Singh et al.ꎬ 2021). Several species  and microspore sizes from 3 - 5 individuals were
   have recently been described and illustrated around the  measured using Photoshop CS5 (Adobe Systems Inc.ꎬ
   world (Mora ̄Olivo et al.ꎬ 2016ꎻ Schafran et al.ꎬ 2016ꎻ  USA).
   Pereira et al.ꎬ 2016ꎬ 2017aꎬ 2019ꎻ Li et al.ꎬ 2019ꎻ Lu  To determine the chromosome numberꎬ young root
   et al.ꎬ 2021). In Chinaꎬ seven species — I. yunguiensis  tips of the sporophytes were pretreated in a saturated
   Q. F. Wang & W. C. Taylorꎬ I. hypsophila Hand.  ̄  aqueous solution of p ̄dichlorobenzene for 3 - 5 h and
   Mazz.ꎬ I. taiwanensis De Volꎬ I. shangrilaensis X. Li &  subsequently fixed in Carnoy’s solution (1 ∶ 3ꎬ glacial
   Y.Q. Huangꎬ I. baodongii Y. F. Guꎬ Y. H. Yan & Yi  acetic acid ∶ 95% ethanol ) for 1 h at 4 ℃.
   J. Luꎬ I. sinensis T. C. Palmer and I. orientalis H. Liu &  Subsequentlyꎬ the samples were hydrolyzed with a
   Q.F. Wang — have been reported ( Handel ̄Mazzettiꎬ  mixture of 3% cellulase and 2.5% pectinase for 10 min
   1923ꎻ Palmerꎬ 1927ꎻ De Volꎬ 1972ꎻ Wang et al.ꎬ    at room temperature. They were then stained with carbol
   2002ꎻ Liu H et al.ꎬ 2005ꎻ Zhang & Taylorꎬ 2013ꎻ Li et  fuchsin. The chromosomes of the samples were counted
   al.ꎬ 2019ꎻ Lu et al.ꎬ 2021).                      and photographed using a Carl Zeiss Axio Scope A1
       We conducted several field surveys of the genus in  photomicroscope (Jenaꎬ Germany).
   China and collected some tetraploid samples (2n = 4x =
   44) previously considered as I. sinensis (2n = 4x = 44)  2  Taxonomic Treatment
   with morphological and anatomical variation (Liu et al.ꎬ
   2004ꎻ Liu et al.ꎬ 2006ꎻ Dai et al.ꎬ 2020ꎬ 2021). By  2.1 Isoëtes longpingii Y.H. Yanꎬ Y.F. Gu & J.P. Shu
   comparing morphological features and spore texturesꎬ  (Fig. 1ꎬ Fig. 3: A-D)
   these samples from Ningxiang City and Tongdao County  Diagnosis: — Isoëtes longpingii is similar to
   in Hunan Province were found to be different from  I. sinensisꎬ but differs in its small megaspores (310-410
   I. sinensis. In additionꎬ our plastid phylogenomic  μmꎬ mean = 350 μmꎬ n = 20)ꎬ sparsely tuberculate ̄
   analysis  indicated  that  these  samples  formed  cristate [ vs. larger ( mean 410 μm )ꎬ densely
   monophyletic cladesꎬ which did not cluster together  tuberculate ̄cristate] and bilobed rhizome corms ( vs.
   with I. sinensis. The sample from Ningxiang Cityꎬ here  trilobed in I. sinensis). It is also similar to hexaploid
   named I. longpingiiꎬ is similar to I. orientalis (2n = 6x =  I. orientalisꎬ but differs in its megaspores tuberculate ̄
   66 ) on megaspore ornamentation and that from     cristateꎬ and 44 chromosomes (vs. 66 in I. orientalis)
   Tongdao Countyꎬ here named I. xiangfeiꎬ is similar  (Fig. 3ꎬ Fig. 4ꎬ Table 1).
   to I. yunguiensis (2n = 2x = 22) on megaspore ornamen ̄  Type: — CHINA. Hunan Provinceꎬ Changsha Cityꎬ
   tation. These two new species are described and   Ningxiang Cityꎬ Yujia ’ ao Villageꎬ 28°14′27.91″ Nꎬ
   illustrated in the present study.                 112°17′44.86″ Eꎬ alt. 131 mꎬ June 15ꎬ 2019. Zhiguo Ou
                                                     YYH15160 ( holotypeꎬ PE! barcode      02347221ꎻ
   1  Materials and Methods                          isotype: NOCC!ꎬ IBSC!).
                                                         Description: — Plants aquatic. Rhizome corms:
       Isoëtes species possess prominent spore morpholo ̄  2 ̄lobed. Sporophylls: widely spreadingꎬ 40 - 60 in a
   gical characteristicsꎬ and the spore ornamentation  tuftꎬ white at baseꎬ green aboveꎬ spirally arrangedꎬ 20-
   terminology established by Hickey (1986) was used in  60 cm longꎬ ca. 1 mm wideꎬ flattened on the adaxial
   the present study. Megaspores and microspores of  sideꎬ rounded on the abaxial sideꎬ base flat and alateꎬ
   samples were examined under a scanning electron   peripheral fibrous bundles presentꎬ central intrastelar
   microscope. Spores were mounted on a double ̄sided  canal 4. Sporangia: basalꎬ obovateꎬ 3.5-4.5×2.5-3.0
   adhesive tape attached to metal stubsꎬ sputter ̄coated  mm. Ligule: cuniformꎬ 2.3 - 2.6 × 1.1 - 1.3 mm. Mega ̄
   with platinumꎬ and observed under a field emission  spores: white when dryꎬ earthy yellow when wetꎬ 310-
   scanning electron microscope ( Quanta 250ꎻ FEIꎬ   410 μm (mean=350 μmꎬ n=20) in diameterꎬ proximal
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