Southwest Desert Flora

The Rhamnaceae or Buckthorn family is a large family of plants cosmopolitan in distribution with the greatest diversity in the tropics and sub-tropics and warm temperate regions such as the southwestern United States.

Species are woody, mainly erect shrubs, trees, some perennial herbs, others twining and/or climbing. Plants may be heavily armed from modified stipules, or unarmed.

Common family characteristics include: Leaves: simple, usually alternate, sub-opposite or opposite, solitary or fascicled, stipules usually present, deciduous or evergreen, petioles often present, bud scales present of absent, leaf blades pinnately veined or 1 to 5 ribbed from base; inflorescence: in North America terminal or axillary cymose clusters or in short shoots, some in panicles or umbels; Flowers: perfect or imperfect, often small and greenish, mostly bisexual or less often monecious, actinomorphic, radially symmetrical, sepals alternate, 4 , 5, petals 0, 4, 5, mostly small and inconspicuous, clawed, distinct, rarely absent, 5 stamens opposite of the petals, usually a single compound pistil; Fruit: capsule or drupes with 1 to 3 stones, 1 or 2 seeded.

Plants of Economic Importance include: The Jujube Tree, Ziziphus jujuba is a large shade tree from China that also bears edible fruit. Ceanothus is an important genus, endemic to North America with beautiful native and ornamental species as well.

The largest genera worldwide include; Phylica, Rhamnus, Ceanothus, Gouania, Cryptandra, Ziziphus and Berchemia.

In North America there are 21 genera with 206 accepted taxa overall. World-wide The Plant List includes 839 accepted species with 53 plant genera.

The largest genera in North America include; Ceanothus, Rhamnus, Colubrina, Ziziphus, Condalia and Frangula.

Arizona Rhamnaceae are all shrubs or small trees, simple leaves, small flowers, perfect or unisexual, with or without petals. Many species within Rhamnaceae have value as winter browse for deer.