Taxonomy of Azolla was extensively studied, but still its identification based on morphological, physiological, and reproductive structure remains unclear. Hence, an attempt was made to differentiate Azolla strains based on morphological and physiological traits, keeping six known Azolla (Azolla microphylla, Azolla caroliniana, Azolla mexicana, Azolla rubra, Azolla filiculoides, and Azolla pinnata) as reference for this study. The results showed that out of 96, 21 strains were sporulated during December, 2017 to February 2018 along with two known species, i.e., A. microphylla and A. pinnata. All sporulating strains (except GSMI 1) showed morphological-resemblance with A. pinnata, whereas GSMI 1 was resembled with A. microphylla. Biplot principal coordinate analysis (PCoA) based on physiological data revealed that GSMI 1 was significantly resembled with A. microphylla. Moreover, the presence of rounded dorsal leaf lobe in A. caroliniana has made it unique in Euzolla sub-section and hence, differentiated from other four species (A. microphylla, A. mexicana, A. rubra, and A. filiculoides). WinRHIZO-based root-imaging technique showed the presence of thick root hairs in A. pinnata as compared to other Azolla strains, whereas efficiency of photosystem II (F_v /F_m, a chlorophyll fluorescence-imaging derived value) and relative growth rate were found higher in CRRI 4. In conclusion, the present study generated a presumptive classification key of 102 strains of Azolla for the first time, which indicates clearly that taxonomy in Azolla should be reviewed. Validation of these characters through molecular markers will give further insight about their classification.

满江红的分类学已被广泛研究，但其基于形态、生理和生殖结构的鉴定仍不清楚。因此，曾试图区分满江红菌株基于形态和生理性状，保持6已知满江红（小叶满江红，满江红鱼草，满江红墨西哥，满江红杨梅，细叶满江红和满江红红豆）作为此研究的参考。结果表明，在 2017 年 12 月至 2018 年 2 月期间，在 96 个菌株中，有 21 个菌株与两个已知物种一起形成孢子， 即， A. microphylla 和 A. pinnata。所有孢子形成菌株（GSMI 1 除外）都显示出与A. pinnata 的形态相似性 ，而 GMSI 1 与A. microphylla相似 。基于生理数据的双标主坐标分析 (PCoA) 显示，GSMI 1 与小叶 A.非常相似 。 此外，A. caroliniana中圆形背叶的存在  使其在 Euzolla 亚节中独一无二，因此与其他四种物种（A. microphylla、A. mexicana、  A. rubra和A. filiculoides 不同））。基于 WinRHIZO 的根部成像技术显示 ，与其他Azolla 菌株相比 ，A. pinnata 中存在较厚的根毛 ，而光系统 II 的效率（F _v  / F _m，叶绿素荧光成像衍生值）和相对生长速率则为在CRRI 4.发现更高总之，本研究中产生的102个菌株的推定分类键满江红首次，这表明清楚地分类在满江红进行审查。通过分子标记验证这些特征将进一步了解它们的分类。