识别要点：Isoetes shangrilaensis is similar to I. hypsophila, but different in both spore size and ornamentations: megaspore size
(207.25–273.09 μm vs. 361.13–510.49 μm in I. hypsophila), megaspore morphology (tuberculate to rugulate megaspore vs. laevigate megaspore in I. hypsophila), and microspore morphology (echinate to cristate microspore vs. bacculate to rugulate microspore in I. hypsophila).
形态特征：沉水水生植物。根茎3浅裂。叶基部白色，上面绿色，螺旋状排列，展开，长28.51-178.42毫米，中部宽约1毫米，12-20个簇生，上侧扁平，下侧圆形，基部具翅；叶舌三角形，骤尖；膜质盖发育不完全，仅覆盖孢子囊的远侧边缘。孢子囊基部，椭圆形，长约1.3-5.6 x 1.7-4.5毫米。大孢子直径207.25-273.09μm（平均244.71μm）；近端表面光滑具一些鳞片，球状或扁球形。小孢子，长11.21-23.66μm（平均19.41μm）；近端表面粗糙，棘状到鸡冠状表面。
