Recent treatments have recognised seven species indigenous to New Zealand in the fern genus Adiantum. Most of these species display dimorphism with respect to the presence or absence of hairs on the abaxial pinna surfaces, or the nature of the hairs themselves. Taxonomic treatment of these dimorphisms has not been consistent, with variation sometimes treated at the specific or varietal levels, or not recognised at all. Morphological variation in the pinna hair characters of all indigenous species is examined here, and the taxonomic significance of the variation reassessed to bring a consistent approach to classification in New Zealand Adiantum. It is concluded that glabrous and hairy variants should not be given taxonomic recognition, but should be considered dimorphisms within those species that are distinguished on the basis of other morphological characters. As a consequence, A. viridescens is reduced to synonymy with A. fulvum, since the two cannot be distinguished by any character other than the glabrous or hairy nature of the pinnae.

最近的治疗方法已在蕨类植物铁线蕨属中确认了新西兰本土的七个物种。这些种类中的大多数相对于耳廓背面的毛发的存在或不存在或毛发本身的性质表现出二态性。这些二态性的分类学处理方法不一致，有时会在特定或品种水平上对变异进行处理，或者根本无法识别。在此检查了所有土著物种的耳廓毛特征的形态学变异，并对变异的分类学意义进行了重新评估，从而为新西兰铁线蕨的分类带来了一致的方法。。结论是，不应给予无毛和毛状变体分类学上的识别，而应将其视为根据其他形态学特征加以区分的那些物种内的二态性。结果，A。viridescens被简化为A. fulvum的同义词，因为除了耳廓的无毛或多毛的性质，二者无法区别。