XXVIII. BURSERACEÆ.
Trees or shrubs, with resinous bark and wood. Leaves alternate, pinnate, without stipules. Flowers perfect or polygamous, in clustered racemes or panicles; calyx 4—5-lobed, the lobes imbricated in the bud, persistent; petals 4—5, imbricated in the bud, distinct or slightly united, deciduous; stamens twice as many as the petals, inserted under the annular or cup-shaped disk; filaments distinct, subulate; anthers introrse, 2-celled, the cells opening longitudinally; pistil of 2—5 united carpels; ovary 2—5-celled; styles united; stigma 2—5-lobed; ovules 2 in each cell, pendulous, collateral, anatropous; micropyle superior; raphe ventral. Fruit drupaceous. Seeds without albumen; seed-coat membranaceous; embryo straight; cotyledons foliaceous; radicle short, superior.
Of the sixteen genera of this family, which is widely distributed through the tropics of the two hemispheres, one only, Bursera, occurs in the United States, reaching the shores of southern Florida with an arborescent species, and southern California and Arizona with another species.