Justicia adhatoda L. (Acanthaceae), an Old-World species of Justicia, is found in almost all geographical regions of India. Indian botanists have persistently used two accepted synonyms of J. adhatoda, namely, Adhatoda vasica and Adhatoda zeylanica, treating them as names of separate species, but without considering or making any reference to variation of forms in the species. Here, different aspects of variation—phenotypic, genotypic, and distributional—in Indian populations of J. adhatoda were studied to determine whether the two names might have been used to designate distinguishable forms of the species. We conducted field studies in different regions of India, laboratory studies of diverse phenotypic traits in experimental plots (anatomical, biochemical, reproductive, and morphometric), and a preliminary study of genetic variation using homologous cytochrome P450 gene fragments. We assessed herbarium samples from across India and the taxonomic literature for pointers indicating the presence of distinguishable forms. Population-level phenotypic and genetic variation pointed to the presence of two distinct morphotypes of the species, which separately tend to occur in dry and wet regions. Each form retains its original phenotype, either when the two forms are transplanted and cultivated together, or when found growing in regions (presumed introduced) outside its normal distributional range. Morphological studies and metabolic profiling (leaf and seed fatty acids, wax load and wax composition in leaf) suggest functional adaptation of the two forms, one to drier and the other to wetter regions. We could distinguish these forms in herbarium specimens dating back to 1821, but neither herbarium specimens nor the taxonomic literature reveal any reference to two forms. We propose that the forms be recognized as two distinct morphotypes of Justicia adhatoda.

Justicia adhatoda L.（Acanthaceae）是Justicia的一种旧世界种，在印度几乎所有地理区域都可以找到。印度植物学家一直使用J. adhatoda的两个公认同义词，即Adhatoda vasica和Adhatoda zeylanica，将它们视为独立物种的名称，但未考虑或未提及该物种的形式变化。在这里，印度血吸虫J. adhatoda群体的变异的不同方面（表型，基因型和分布）进行了研究，以确定这两个名称是否可能已用于指定物种的可区分形式。我们在印度不同地区进行了实地研究，在实验区（解剖，生化，生殖和形态计量学）中对各种表型特征进行了实验室研究，并使用同源细胞色素P450基因片段对遗传变异进行了初步研究。我们评估了来自印度各地的植物标本室样本和分类学文献，以寻找指示可区分形式的迹象。群体水平的表型和遗传变异指出该物种存在两种不同的形态型，它们分别倾向于在干燥和潮湿的地区发生。两种形式都一起移植和培养时，每种形式都保留其原始表型，或发现其生长在其正态分布范围之外的区域（假定为已引入）。形态学研究和代谢谱分析（叶和种子脂肪酸，叶中的蜡含量和蜡成分）表明两种形式的功能适应性，一种形式更干燥，另一种形式更湿润。我们可以在1821年的植物标本室标本中区分这些形式，但是植物标本室和分类学文献均未提及这两种形式。我们建议将这些形式识别为两种不同的形态 我们可以在1821年的植物标本室标本中区分这些形式，但是植物标本室和分类学文献均未提及这两种形式。我们建议将这些形式识别为两种不同的形态 我们可以在1821年的植物标本室标本中区分这些形式，但是植物标本室和分类学文献均未提及这两种形式。我们建议将这些形式识别为两种不同的形态Justicia adhatoda。