Graythorn
Ziziphus obtusifolia
ARMED: Many, long stout thorns with one or more vestigial leaf nodes.
LEAVES: Oblong leaves can be small or medium sized and are deciduous
with drought or frost leaving the gray-green stems, including the thorns, to
conduct photosynthesis.
FRUIT: A blue-black berry about 1 cm dia. containing one hard seed.
SHRUB: A medium to very large shrub in Arizona. The shrubs grow
especially large (3 to 5 m) on flood plains near rivers where they tap into
ground water.
FLOWERS: Small cream flowers have five petals, five stames and a
distinct floral disc (hypanthium).
RANGE:Found commonly throughout much of the Sonoran Desert of Arizona.
Most common along washes and river flood plains.
In the illustration at left notice that on the stem just above the cut there is a series of scars in the bark. These were created by the egg-laying activities of a female cicada. These are the familiar loud buzzing insects of midsummer. Only the males buzz for purposes of attracting a mate. The female possesses a sharp ovipositor and inserts her eggs into young, still tender twigs of trees and shrubs. The scars remain visible for several years.