Sem studies on vessel elements of Saururaceae

Vessel elements in Anemopsis have simple perforation plates and alternate (sometimes scalariform) lateral wall pitting; Anemopsis has tracheids with large, densely placed pits. These conditions are in contrast with tracheary element features of Gymnotheca, Houttuynia, and Saururus, in which perforation plates are scalariform (many with notably slender bars) and with scalariform lateral wall pitting. Porose pit membrane remnants, which cannot be seen with light microscopy, are newly reported in Houttuynia and Saururus. These porose pit membranes underline the primitive nature of vessels in Gymnotheca, Houttuynia, and Saururus. The highly specialized vessels of Anemopsis may relate to entry into seasonally dry habitats, whereas Gymnotheca, Houttuynia, and Saururus may have experienced unbroken occupancy of mesic habitats.