1. Exochorda racemosa (Lindl.) Rehder (common pearlbush)
Map 2443
Plants shrubs,
1–3 m tall, with several slender trunks. Branches sometimes developing lateral
short shoots, but unarmed. Bark orangish brown, brown, and gray, peeling in
variously colored plates on older trunks, usually reddish brown to dark gray
and with scattered small lenticels on branches. Twigs tan to reddish brown,
becoming dark gray, angled, glabrous. Winter buds lateral and terminal,
narrowly ovoid to narrowly conic, bluntly to occasionally sharply pointed at
the tip, with several overlapping scales, glabrous. Leaves alternate,
occasionally appearing more or less whorled at the tips of short branches,
rolled lengthwise during development, sessile or more commonly short-petiolate,
the petioles glabrous. Stipules absent. Leaf blades simple, unlobed, elliptic
to oblong-elliptic, oblong-obovate or narrowly obovate, rounded or bluntly and
broadly pointed at the tip, often with a minute, sharply pointed extension of
the midvein at the very tip, tapered at the base, the margins entire or
shallowly wavy, scalloped, or toothed toward the tip, the teeth not
gland-tipped, the surfaces glabrous, the undersurface pale, the venation
pinnate. Inflorescences terminal, racemes of 4–10 flowers, these produced after
the leaves develop, the axis and stalks glabrous at maturity, sometimes
sparsely hairy when young, the flower stalks 3–12 mm long, each with a small
bract at the base, the lowest of these leaflike, grading upward to small,
narrowly oblong-elliptic, and scalelike, mostly persistent, each flower also
with a pair of small bractlets near the tip of the stalk, these linear to
narrowly oblong, white, shed early. Flowers perfect or usually functionally
staminate or pistillate (mixed in the same inflorescence), shallowly
perigynous, not fragrant, the hypanthium not fused to the ovary above its base,
saucer-shaped to shallowly bell-shaped, persistent as a small disc, glabrous.
Sepals 5, 2–3 mm long, loosely ascending to spreading at flowering, triangular,
mostly sharply pointed at the tip, the margins entire, the surfaces glabrous,
shed after flowering. Petals 5, 12–20 mm long, obovate to nearly circular,
short-tapered to a short, stalklike base, white. Stamens 15–20, exserted, the
filaments attached on the disc, the anthers yellow. Pistil 1 per flower, of 5
loosely fused carpels. Ovary superior, with 5 locules containing 2 ovules (1 of
these usually abortive). Styles 5, erect and appressed but not fused, the
stigmas small, capitate. Fruits capsules, 6–10 mm long, broadly obovate to
broadly oblong or depressed-circular in outline, deeply 5-lobed, the lobes
appearing more or less flattened and semicircular in outline, glabrous, brown
to gray at maturity, dehiscing from the tip, persistent after the seeds are
shed, the lobes sometimes breaking apart (the joined surfaces usually pale and
appearing densely short-hairy), with usually 1 seed per locule, this 5–9 mm
long, irregularly oval to oblong-elliptic or semicircular, strongly flattened,
with a complete or incomplete wing around the margin, the surface brown to dark
brown, glabrous, smooth. 2n=16, 18. April–May.
Introduced,
uncommon, known thus far only from Franklin County (native of Asia, introduced
sporadically in the eastern U.S. west to Missouri and Louisiana). Disturbed
mesic upland forests.
This species was
first collected in 2006 by Nels Holmberg at the Shaw Nature Reserve, where
plants escaped from an old planting into an adjacent forest.