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Stillingia
sylvatica Garden ex L. Standardized Common
Name: Stillingia
Other Common Names: Nettle Potato,
Queen’s Delight, Queen’s Root, Silver Leaf, Yaw Root
Family: Euphorbiaceae
Taxonomy: Stillingia
includes about 30 species, most native to tropical regions of the New World. Stillingia
sylvatica is one of two species that are native to the southeastern United
States. The other of these, S. aquatica Chapm., is relatively uncommon
and confined to swampy habitats; nevertheless, the two species are known to
hybridize.
Description: Perennial herb or
subshrub with milky latex. Stems and roots arising from a woody cylindrical
rhizome; roots widely spaced, long, cylindrical, woody. Stems usually several,
erect to spreading, 0.2–1.2 m high, herbaceous to slightly woody, unbranched or
dichotomously branching; older bark cracked and reddish. Leaves alternate,
variable, elliptic to oblanceolate or obovate, 2–12 cm long, green or red; base
tapering, petiolate or sessile; apex acute, rounded, or emarginate; margins
serrulate to crenulate; midrib prominent. Flowers unisexual, plants monoecious;
inflorescence a terminal spike of cymules, 2.5–13 cm long; male and female
flowers tiny, borne in separate clusters, subtended by bracts. Male flowers in
clusters of 5–13; calyx shallowly 2-lobed; stamens 2. Female flowers solitary;
sepals 3; ovary 3-loculed, with 3 styles. Fruit a septicidal capsule, 6–12 mm
in diameter; seeds 3, 4–8 mm long.
Parts
in Commerce:
Root with rhizome, usually dried
Identification:
- Long cylindrical
pieces, 0.5–3 cm in diameter, tapering; branches few
- Surface brown,
or reddish where outer layers are damaged, longitudinally wrinkled
- In
cross-section, shows thin reddish cork layer; fairly thick ring of
parenchyma including secondary cortical (pericycle) and phloem zones,
containing brownish resin cells; distinct cambium layer; broad central
cylinder of pale xylem in numerous wedges separated by very thin
parenchyma rays
- Cork and phloem
in fresh material often easily separating from xylem, so bark can be
peeled away or pulled off in a cylinder
- Fracture fibrous
- Odor
characteristic
- Taste pungent,
bitter
Confusion
with other species has not been reported. Stillingia aquatica, which
looks quite different from S. sylvatica, does not have long woody roots;
instead, numerous slender secondary roots are borne on a single short taproot.
References:
Radford AE, Ahles HE, Bell CR. Manual of the
Vascular Flora of the Carolinas. Chapel Hill, NC: University of North
Carolina Press; 1968.
Rogers DJ. A revision of Stillingia in the
New World. Ann Missouri Bot Gard. 1951;38:207–259.
Wunderlin RP. Guide to the Vascular Plants of
Florida. Gainesville: University Press of Florida; 1998.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:530–533.
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