ABSTRACT
Anatomical data regarding the climbing modes and cambial variants of the
stem transverse section in the Menispermaceae in Taiwan are lacking. Here, we
examined the climbing modes and anomalous structure of climber stems in this
family. Reviewing the previous reports of cambial variants in angiosperm liana
families, a list of angiosperm liana families processing specified types of
cambial variants and the terms based on description for the transverse section
of a stem were provided. The results show that Cocculus laurifolius DC. is a shrub, Stephania cephalantha Hayata and Stephania longa Lour. are
vines, and the remaining 13 species are lianas. In all species, the climbing mode was twining and dextrorse
stems. The anomalous structure of the
stem comprised successive
cambia in Cocculus laurifolius, a
combination of xylem in plates and dissected xylem in Cocculus orbiculatus (L.) DC., and xylem in plates in the remaining
14 species. In the genus Cyclea,
parenchyma proliferation from the secondary xylem resulted in the development
of 1 - 3 linear lobes in each collateral vascular bundle. The vessel diameter
of C. laurifolius is <50 μm which
is the smallest size due to shrub in its life stage. C. orbiculatus had the longest collateral vascular bundles,
longest rays and widest rays. Cyclea
ochiaiana (Yamam.) S. F. Huang & T. C. Huang had the widest collateral
vascular bundles. Sinomenium acutum (Thunb.)
Rehder & E. H. Wilson had the highest vessel density. Tinospora crispa (L.) Hook. F. et Thoms develops blunt tubercles on
the epidermis and Stephania tetrandra S. Moore bears conspicuous phellem layer. Those findings, such as the climbing
mode, the features of parenchyma proliferation, the features of collateral
vascular bundles (number, width, length), dimorphic vessels, and size and density
of vessels, highlight new anatomical characteristics for species identification
in the Menispermaceae in Taiwan.