Am J Bot. 1998 Jul;85(7):1028.
Ferns in which vessels have been demonstrated to date are phylogenetically relatively specialized and characteristic of habitats with marked extremes in temperature and water availability. These specifications do not apply to the Gleicheniaceae, which indicates that vessels may occur in a range of more primitive ferns, including those from more nearly mesic habitats. Vessels in Dicranopteris have perforation plates (both lateral and terminal) with morphology similar to that of lateral wall pitting as seen with light microscopy. Scanning electron microscopy (SEM) is therefore necessary to demonstrate presence of perforations. Vessel presence in Dicranopteris is important in forming a picture of vessel presence and specialization in ferns, the phylogenetic and ecological distribution of which may differ from the patterns found in monocotyledons and dicotyledons. We believe that presence of vessels may not be a reliable indicator of phylogenetic position among ferns.
迄今为止，已在某些蕨类植物中发现了导管，这些植物在系统发育上相对较为特化，并且是具有显著温度和水分可利用性极端变化的生境的特征。这些特征不适用于水龙骨科，这表明导管可能存在于一系列更为原始的蕨类植物中，包括那些来自较近中生境的蕨类植物。凤尾蕨属中的导管具有穿孔板（侧向和末端），其形态与光镜下看到的侧向壁坑洼相似。因此，需要扫描电子显微镜（SEM）来证明穿孔的存在。凤尾蕨属中导管的存在对于形成蕨类植物中导管存在和特化的图像很重要，其系统发育和生态分布可能与单子叶植物和双子叶植物中的模式不同。我们认为，导管的存在可能不是蕨类植物中系统发育位置的可靠指标。
