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