Bulbs, Corms, Tubers And Rhizomes

Press, Volume CIX, Issue 32221, 13 February 1970, Page 9

Bulbs, Corms, Tubers And Rhizomes

The term bulb is used in reference to a number of different types of structures and this rather loose usage calls for correction. Tubers, conns and rhizomes are generally called bulbs in addition to true bulbs. A bulb is best described as an underground bud or modified shoot bearing leaves on a telescoped stem. Enc'osed by scale-like leaves, the terminal bud at the top of the stem develops into the aerial shoot of the plant and the auxiliary buds develop into new bulbs. Examples of bulbs include daffodil, tulip, lily and onion. A corm is a short thick

vertically enlarged under-, ground stem and differs from the bulb in that it is almost entirely made up of stem tissue with relatively few! scale leaves. The buds are borne on the axils of the I scale-like remains of the pre- , vious year's growth. Gladiolus, crocus and inontebretia are representative of corms. A rhizome is an elongated underground stem which possesses a terminal bud and produces lateral buds at the nodes in the axils of the scale leaves These give rise to stems which generally die back each year. Rhizomes are various in form and appearance, unlike bulbs and corms which are fairly regular. A rhizome usually creeps along either at or just below the surface of the soil. Apart from such representatives as Solomon’s seal and iris, rhizomatous plants include some accursed weeds including couch grass (Poa pratensis) and creeping or Californian thistle (Carduus arvensis). The tuber is a swollen endi

1 portion of an underground stem which bears buds in the axils of the scale-like rudimentary leaves. Dahlias represent- the best known (tubers in the flower world.