Morphology and development of foliar epidermis inStylosanthes fruticosa (Retz.) Alston (Syn.S. mucronata Willd.)
Biseriate nature of the leaf epidermis is established in the genusStylosanthes for the first time. Of the two layers derived from the uniseriate protoderm by one periclinal division, the outer one is differentiated into ordinary epidermal cells (very rare), uni- and multi-seriate (shaggy) hairs, para-mesogenous stomata and crystalliferous idioblasts. On the contrary, the inner layer is composed of large and thick-walled cells. This layer is discontinuous beneath the stomata and thus the stomatal pore always opens into the sub-stomatal chamber. The members of the sub-tribe, Stylosanthinae such asStylosanthes andArachis, show the para-mesogenous stomata predominantly whereasZornia possesses aniso-mesoperigenous stomata more commonly. Thus the stomatal evidence supports the transfer of the latter genus to a new sub-tribe, Poiretiinae from its old sub-tribe, Stylosanthinae.