ABSTRACT

The type material of Achnanthes hauckiana Grunow has been investigated using light and scanning electron microscopy. The species, transferred to the genus Planothidium, was frequently reported from brackish and even marine environments. The original Grunow material was collected from a karstic spring near Trieste. Analysis of the material and of samples collected from the Croatian Krka River, resulted in a better understanding of the morphology of Planothidium hauckianum and a better characterization of the diatom flora of which it is a dominant component. The paper compares the species with similar Planothidium species from the P. delicatulum complex and revises published images of P. hauckianum in literature, making it clear that all reported and illustrated brackish populations of P. hauckianum belong to different, often unknown species. The presence of Planothidium hauckianum is limited to karstic spring areas, most likely showing a very restricted biogeographical distribution.

摘要

已使用光和扫描电子显微镜研究了拟南芥（Achnanthes hauckiana Grunow）的类型材料。该物种被转移到Planothidium属中，经常在微咸甚至海洋环境中被报道。Grunow的原始材料是从的里雅斯特附近的岩溶泉中采集的。对从克罗地亚克尔卡河采集的材料和样品进行的分析，使人们更好地了解了Planothidium hauckianum的形态，并更好地表征了作为主要成分的硅藻菌群。本文比较了该物种与P. delicatulum复合体中相似的Planothidium物种，并修改了已发表的图像。文献中的P. hauckianum清楚地表明，所有已报道和图解的咸淡淡的P. hauckianum种群都属于不同的，通常未知的物种。太极齿藻的存在仅限于岩溶的春季地区，最有可能显示出非常有限的生物地理分布。