Although nectaries are widely known among angiosperms, few records exist for ferns, and there are even fewer studies focusing on their anatomy. We noticed nectaries in Serpocaulon (Polypodiaceae) and confirmed their presence in six taxa of the genus. We conducted a structural analysis using light and scanning electron microscopy and revised occurrence records of nectaries in polypodiaceous ferns. Nectar secretion was observed in young fronds and was restricted to the basal pinnae/segments. We did not detect any differentiated glandular tissue in the portions where the nectar was released, which implies that the nectar secreting glands in the studied taxa should be regarded as non-structural nectaries. Nonetheless, we found the mesophyll in these portions to usually be compact (i. e. with inconspicuous and relatively fewer intercellular spaces), sometimes with cells with distinct dense protoplast. In addition, prominent stomata with elevated guard cells were observed in nectary portions, probably constituting pathways through which nectar exudates. An update record for nectaries in Polypodiaceae was presented; these structures were recorded in 8% of Serpocaulon and ca. 1% of the species of the family, most being epiphytic with pinnatisect laminae dissection. While extrafloral nectaries are mostly related to protection against herbivores, nectary ecology in ferns is poorly understood, and a protective role of these structures cannot be discarded. However, further investigation is needed and encouraged to develop a comprehensive understanding of fern nectaries in light of their evolutionary history and ecological roles.

尽管蜜腺在被子植物中广为人知，但蕨类植物的记录很少，而且关注其解剖结构的研究甚至更少。我们注意到塞尔波考隆的蜜腺（Polypodiaceae）并证实它们存在于该属的六个分类群中。我们使用光学和扫描电子显微镜进行了结构分析，并修订了多足蕨类植物蜜腺的发生记录。在幼叶中观察到花蜜分泌并且仅限于基部耳廓/节段。我们在释放花蜜的部分没有检测到任何分化的腺体组织，这意味着所研究的类群中的花蜜分泌腺应被视为非结构性蜜腺。尽管如此，我们发现这些部分的叶肉通常是紧凑的（即具有不显眼且相对较少的细胞间隙），有时细胞具有明显致密的原生质体。此外，在蜜腺部分观察到具有升高保卫细胞的显着气孔，可能构成花蜜渗出的途径。提交了一份蓼科植物蜜腺的更新记录；这些结构被记录在 8% 的Serpocaulon和ca。该科的 1% 的物种，大多数是附生的，有羽状叶解剖。虽然花外蜜腺主要与对食草动物的保护有关，但对蕨类植物的蜜腺生态知之甚少，并且不能忽视这些结构的保护作用。然而，根据蕨类植物的进化历史和生态作用，需要并鼓励进一步调查以全面了解蕨类植物的蜜腺。