On the occurrence of stone-cells in twelve species of clerodendron
Twelve locally available species ofClerodendron have been examined for a comparative study of stone-cell structure, distribution and ontogeny. The species fall into two classes. First group includesC. fragrans, C. infortunatum, C. splendens andC. minahassae which have brachysclereids developed from transformed parenchyma cells of cortex or pith. The second group includesC. aculeatum andC. inerme which have “spheroidal sclereids” formed by the conversion of the collenchyma cell of the cortex. This has not been, as I am aware, reported so far. Both types develop by the “secondary sclerosis” of either the parenchyma cell or the collenchyma cell. So far as has been noticed, stone-cells seem to be present only in those species where the sclerenchyma or the phloem fibres are absent. It is therefore suggested that probably they both serve the same function of giving mechanical strength to the plant body. It has also been pointed out in view of the occurrence of some kind of crystals in these stone-cells, that they may be functioning as the repositories of excretory or secretory products.