Rhamnus lanceolata Pursh - Buckthorn
Family - Rhamnaceae
Stems - Woody, a shrub to +2m tall. Twigs glabrous, tannish-red, terete. New growth terete, glabrous or puberulent. Pith of the twigs white, spongy, solid.
Leaves - Leaves alternate, petiolate. Petioles to 5mm long, pubescent on the adaxial margin and with an adaxial groove. Blades lanceolate to elliptic, serrulate, acute, mostly glabrous but with some hairs on the midrib below, deep dull green adaxially, shiny light green abaxially, to +5cm long, +2cm broad.
Inflorescence - Single flowers from the leaf axils on the new-season's growth. Pedicels 3-4mm long, glabrous. Plants polygamodioecous (with male and female flowers on different plants and with some perfect flowers on the same plant).
Flowers (staminate) - Petals 4, alternating with the sepals, adnate at the apex of the calyx tube, erect, folded around the stamens, small, 1-1.3mm long, .5mm broad, glabrous, purplish, notched at the apex. Stamens 4, alternating with the calyx lobes, erect, adnate just below the petals. Filaments -1mm long, compressed, widest at the base and tapering to the apex, glabrous, translucent-green. Anthers to .7mm long, whtish to gold. Pistil reduced, .5-.6mm long, glabrous, green, superior, tapering to the apex. Calyx tube green, glabrous, 1-1.5mm long. Sepals 4, 2mm long, 1mm broad, acute, entire, green and sometimes with brown tips.
Flowering - April - June.
Habitat - Open wooded slopes, usually on limestone.
Origin - Native to U.S.
Other info. - This shrubby species can be found throughout most of Missouri but is apparently absent from the bootheel counties of the state. The plant is fairly non-distinct and easily missed when traversing the woods. Habitat is probably the best character to use when trying to locate this plant in the wild. In the Ozarks this species is not nearly as common and the larger R. caroliniana Walt.
Photographs taken at Whetstone Creek Conservation Area, Callaway County, MO., 5-2-04.