Lagena has so far only been known from the scarcely reported but widespread species Lagena radicicola, which is a parasite of root epidermal cells. While it was mostly reported from a wide range of cereals and other grasses, it has been shown to affect some dicot species under, e.g. tobacco and sugar beet. Due to the wide host spectrum under laboratory conditions, there were no attempts to subdivide the genus into several species, even though some morphological differentiation was reported and the species had been found in several continents. During a survey of diatoms, we came across some parasitoids that would have previously been assumed to be members of the genus Lagenidium. The species exhibited rather narrow host specificity in nature. One species was brought into dual culture with host diatoms of the genus Ulnaria, but could not be transferred to other host genera. Surprisingly, phylogenetic analyses revealed that Lagena radicicola was in a sister clade to that formed by the diatom parasitoids, suggesting a versatile pathogenicity of the genus. Interestingly, several phylogenetic lineages only known from environmental sequencing were clustered with the species found in this study, hinting an undiscovered diversity in the genus Lagena.

迄今为止， Lagena仅从很少报道但分布广泛的物种Lagena radicicola中得知，它是根表皮细胞的寄生虫。虽然它主要来自各种谷物和其他草类，但已证明它会影响某些双子叶植物物种，例如烟草和甜菜。由于实验室条件下宿主谱广，没有尝试将该属细分为几个物种，尽管报告了一些形态分化并且该物种已在几个大陆被发现。在对硅藻的调查中，我们发现了一些以前被认为是Lagenidium属的寄生蜂. 该物种在自然界中表现出相当狭窄的宿主特异性。一个物种被带入与Ulnaria属的寄主硅藻进行双重培养，但不能转移到其他寄主属。令人惊讶的是，系统发育分析显示Lagena radicicola是由硅藻寄生蜂形成的姐妹进化枝，表明该属具有多种致病性。有趣的是，仅从环境测序中得知的几个系统发育谱系与本研究中发现的物种聚集在一起，暗示了Lagena属中未被发现的多样性。