Abstract

The Blechnaceae is a family of leptosporangiate ferns with a wide geographical distribution. Recent phylogenies revealed several lineages within the family, culminating in a classification system comprising 25 recognized genera grouped into three subfamilies. Spore surface morphology has major importance in the taxonomy of the group, but there is limited information on the relevance of other palynological characters. This study aimed to examine whether spore morphology aids in distinguishing genera of Blechnaceae according to the current phylogenetic classification. Spores from 28 species distributed in 12 genera of the subfamilies Blechnoideae, Stenochlaenoideae, and Woodwardioideae were examined. Specimens were acetolyzed, measured, described, and illustrated using light and scanning electron microscopy. The analyzed spores were medium to large in size, with a monolete scar of varied size, straight, and without margo. The perine was three-layered, except in the subfamily Stenochlaenoideae, which showed a single-layered perine. Blechnoideae was the most palynologically diverse subfamily. Woodwardioideae and Stenochlaenoideae spore characters had high diagnostic value for identification at the genus level. Austroblechnum and Blechnum showed high similarity; no single spore character could be used to discriminate between species of these genera. Blechnum anthracinum was the only species within its genus to exhibit cristate spores, with filaments and perforations. Morphometric analysis did not prove to be a useful tool for differentiating subfamilies or genera, possibly because of the influence of polyploid individuals. This investigation revealed unique spore characters for some genera and provided morphological descriptions that allow identification at the species level, contributing to the taxonomic study of Blechnaceae.

摘要

Blechnaceae 是一个具有广泛地理分布的细孢子蕨科。最近的系统发育揭示了该家族内的几个谱系，最终形成了一个分类系统，该系统包含 25 个公认的属，分为三个亚科。孢子表面形态在该类群的分类学中具有重要意义，但关于其他孢粉学特征的相关性信息有限。本研究旨在根据当前的系统发育分类检查孢子形态是否有助于区分 Blechnaceae 属。对分布在 Blechnoideae、Stenochlaenoideae 和 Woodwardioideae 亚科 12 个属中的 28 个物种的孢子进行了检查。使用光学和扫描电子显微镜对样本进行乙酰水解、测量、描述和说明。分析的孢子大小为中到大，有大小不一的单核疤痕，直的，没有margo。除了 Stenochlaenoideae 亚科显示单层会阴外，会阴是三层的。Blechnoideae 是孢粉学上最多样化的亚科。Woodwardioideae和Stenochlaenoideae孢子特征对属水平鉴定具有较高的诊断价值。Austroblechnum和Blechnum表现出高度的相似性；不能用单一的孢子特征来区分这些属的物种。Blechnum anthracinum是其属内唯一一种显示出具细丝和穿孔的嵴孢子的物种。形态测量分析并未证明是区分亚科或属的有用工具，这可能是因为多倍体个体的影响。这项调查揭示了一些属的独特孢子特征，并提供了允许在物种水平上进行识别的形态描述，有助于 Blechnaceae 的分类学研究。