Buds

A bud is a compressed growing point protected by scale leaves, in which the internodes have not yet elongated and the young leaves remain closed and crowded; as a bud develops, its internodes elongate and its leaves spread out, and it may grow into a branch or terminate in a flower/inflorescence. Buds are classified by origin and by function. By origin: a terminal (apical) bud sits at the tip of the main stem or of a branch; a lateral (axillary) bud sits in a leaf's axil and grows into a branch or flower; an extra-axillary bud forms at a node but outside the leaf axil (Solanum americanum); and an accessory bud is an extra bud beside (collateral) or above (superposed/serial) the axillary bud (Citrus, Duranta). Adventitious buds arise from any part other than the normal stem positions: radical buds arise from lateral roots and grow into new plantlets (Millingtonia, Bergera koenigii, Coffea arabica, Aegle marmelos); foliar buds grow on leaves, from veins or leaf margins (Begonia, Bryophyllum); and cauline buds arise directly from the stem - from cut or pruned ends or from branches - often functioning as tuberous propagules (Dioscorea, Agave). Bulbils are modified, enlarged buds specialised for vegetative propagation: in Agave and Allium proliferum a floral bud itself turns into a bulbil; in Lilium …