Vascular Plants of Williamson County

Prunus caroliniana [Rosaceae]
laurel cherry, carolina laurel cherry

Prunus caroliniana (Miller) Aiton, laurel cherry, carolina laurel cherry. Small tree or shrub, evergreen, as shrub erect and highly branched, in range 350+ cm tall; shoots with only cauline leaves, in shade and on lower branches ± 2–dimensional (plagiotropic), glabrous, glands inconspicuously bumps on blade lower surface, twig when scratched with strong smell of bitter almonds (prussic acid).

Stems

Stems ± cylindric, tough, soon with pimplelike blisters and after forming periderm with fine lengthwise cracks.

Leaves

Leaves helically alternate, simple, petiolate, with stipules; stipules 2, attached to leaf base at node, ± oblong flared at base, 2—6 × 0.6—1.3 mm, acute at tip, light green to purple–red (especially tip and margins); petiole defined by slightly constriction at base, shallowly channeled but not at base, 4—6.5 mm long, often purple–red, firmly attached; blade elliptic to narrowly obovate or widely oblanceolate, in range 37—108 × 12—38 mm, tapered and symmetric at base, entire or finely short–serrate, the teeth 2—4 per 100 mm margin, acute with reddish point at tip, pinnately veined with midrib slightly sunken on upper surface and raised on lower surface, upper surface glossy and smooth, glands widely spaced, small and domed, green or purplish red.

Inflorescence

Inflorescence raceme, axillary, 9—30–flowered, ascending, raceme with all staminate flowers, mixed staminate and bisexual flowers, or rarely all bisexual flowers, bracteate, glabrous; at base of inflorescence with several early–abscising bud scales, scales somewhat fleshy, cupped–triangular, 1—2.5 mm long, white at base and red–purple above, minutely 3–toothed at tip; peduncle (with scales) to 6 mm long; rachis ridged, 8—34 × 1.2—1.4 mm, with ridge descending from each bractlet, greenish white; bractlet subtending pedicel deeply cupped–ovate (pouched), mostly 1.5 mm long, rose (center) and white or aging white, margins somewhat uneven to inconspicuously jagged, on inner surface with minute glandular hairs at base of pouch, the lowest bractlet resembling a long scale often with 3 teeth and red–purple, sometimes appearing with a horizontal ridge, still present after flowering; pedicel cylindric or somewhat crinkled, in range 2—4 mm long, cream–colored or rose at base.

Staminate flower

Staminate flower radial, 6—7 mm across, faintly honey–scented; hypanthium cup–shaped, 2—2.5 × 2.2—2.5 mm, cream–colored on outside (blushed rose) and in bud rounded becoming inconspicuously wrinkled, inner surface in bud yellow–orange aging ligher (white band below rim), nectary nectar–producing from yellow–orange tissue; sepals 5—7 in 1 whorl, formed on rim of hypanthium and mostly covering top of bud, ± erect, broadly ovate to semicircular and strongly cupped, 1—1.5 × 1 mm (sometimes 1 diminutive), rose with white, rounded at top, crinkled; petals 5—7 in 1 whorl, ± spreading aging reflexed, obovate to wedge–shaped or diamond–shaped, in range 1.5—2.4 × 1 mm, white, especially top somewhat jagged; stamens 10—14, free, below the rim of hypanthium opposite each sepal and petal and mostly appearing like 1 ring; filaments alternately long (opposite sepals) and shorter (opposite petals), 2—3 mm long, white, in bud strongly arched inward during pollination ascending to suberect, bases flared and touching, glabrous; pistil 1, vestigial, ca. 0.5 mm long; ovary superior, spheroid, ca. 0.2 mm, colorless; style erect, red–purple.

Bisexual flower

Bisexual flower radial, 6—7 mm across, faintly honey–scented; hypanthium cup–shaped, 2—2.5 × 2.2—2.5 mm, cream–colored on outside (blushed rose) and in bud rounded becoming inconspicuously wrinkled, inner surface in bud yellow–orange aging ligher (white band below rim), nectary nectar–producing from yellow–orange tissue; sepals 5—7 in 1 whorl, formed on rim of hypanthium and mostly covering top of bud, ± erect, broadly ovate to semicircular and strongly cupped, 1—1.5 × 1 mm (sometimes 1 diminutive), rose with white, rounded at top, crinkled; petals 5—7 in 1 whorl, ± spreading aging reflexed, obovate to wedge–shaped or diamond–shaped, in range 1.5—2.4 × 1 mm, white, especially top somewhat jagged; stamens 10—14, free, below the rim of hypanthium opposite each sepal and petal and mostly appearing like 1 ring; filaments alternately long (opposite sepals) and shorter (opposite petals), 2—3 mm long, white, in bud strongly arched inward during pollination ascending to suberect, bases flared and touching, glabrous; pistil 1, 4—5 mm long, proterogynous and exserted in bud before filaments straighten; ovary superior, ellipsoid to narrowly ovoid, ca. 1 × 0.7 mm, glossy light green, 1–chambered with 2 ovules; style erect, cylindric, 3—4 × 0.4 mm, white but pink and rose approaching tip, glabrous; stigmatic tip somewhat furrowed and purple–red.

Fruit

Fruit not observed in range, drupe, 1–stoned, subspheroid, 9—12 mm long, black, glabrous; pulp (mesocarp), leathery, red–purple; stone ovoid.

A. C. Gibson