part_of part of part of vascular leaf leaf base tubercle Found in cacti and other succulents. The upper part of a leaf from which a tubercle develops is usually shed early in development. Tubercles are often conical, but they may merge with those directly above and below to form ribs, as in saguaro (Carnegiea), or they may elongate, as in species of pincushion cacti (Mammillaria). In species with tubercles, the areole bud (PO:0025353) is often found at the distal end of the tubercle. The areole bud originates in the leaf axil (PO:0009023) of the leaf that becomes the tubercle, but is displaced to the tip through elongation of the tubercle. 2011-11-16T02:07:59Z PO:0025352 An enlarged leaf base (PO:0020040) that is fused with adjacent shoot axis (PO:0025029) tissue. plant_anatomy PO_GIT:175 podaria (exact, plural) rwalls podarium (exact) 小塊茎、塊根 (Japanese, exact)