jimsonweed (Datura stramonium)
The common name 'jimsonweed' is probably a corruption of 'James-
town Weed,' referring to where this species was first observed in
Datura stramonium L. var. tatula (L.) Torr.
Datura tatula L.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of jimsonweed
is Datura stramonium L. Two varieties of jimsonweed have been des-
cribed. The typical variety has green stems and white flowers, while var.
tatula has purple stems and pale violet flowers. However, variety tatula
is now generally not accepted; charcteristics subscribed to it are now
seen as morphological variations within the single species.
NATIVE STATUS: Introduced, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This adventive plant is a summer annual about 3-5' tall that branch-
es dichotomously. The stems are green or purple and largely hairless, al-
though young stems often have conspicuous hairs.
Leaves: The alternate leaves are up to 8" long and 6" across (excluding
the petioles). They are ovate or ovate-cordate in outline, but pinnately
lobed. These lobes are somewhat shallow and pointed at their tips; there
are usually 2-3 of these lobes on each side of the leaf blade. The margin
of each leaf may have a few secondary lobes or coarse dentate teeth,
otherwise it is smooth or slightly undulate. The leaves may be slightly
pubescent when young, but become hairless with age; the upper surface
of each leaf is often dark green and dull. The foliage of Jimsonweed
exudes a bitter rank odor.
Flowers: Individual flowers occur where the stems branch dichotom-
ously; the upper stems also terminate in individual flowers. The fun-
nel-form corolla of each flower is up to 5" long and 2" across when
fully open; its outer rim has 5 shallow lobes. Each of these lobes forms
an acute point in the middle.The corolla is white or pale violet through-
out, except at the throat of the flower, where thick veins of dark violet
occur. The light green calyx is shorter than the corolla and conspicuous-
ly divided along its length by 5 membranous wings. The flowers don't
open up fully until around mid- night and close early in the morning;
each flower lasts only a single day.
Fruit/Seeds: Each flower is replaced by a hard fruit that is dry and spiny;
it is about 1½" long, 1" across, and spheroid-ovoid in shape. Underneath
each fruit is a truncated remnant of the calyx that curves sharply down-
ward. These fruits are initially green, but become brown with maturity;
they divide into 4 segments to release the seeds. The large seeds are dull,
irregular, and dark-colored; their surface may be pitted or slightly reticu-
Roots: The root system consists of taproot that is shallow for the size of
the plant; it branches frequently. Jimsonweed spreads by reseeding itself.
REGENERATION PROCESS: Jimsonweed propogates itself by reseed-
HABITAT TYPES: Jimsonweed is probably adventive from tropical
America and was first observed in the United States at the James-
town colony during the 17th century. Typical habitats include cropland
(particularly corn fields), fallow fields, old feed lots, piles of soil at con-
struction sites, mounds of decomposed mulch and discarded vegetation,
and miscellaneous waste areas. Disturbed areas are strongly preferred.
SITE CHARACTERTICSTICS: Jimsonweed prefers full or partial
sun, moist to mesic conditions, and a rich fertile soil with high nitrogen
content. This type of soil is necessary to supply the nutrients that are
required by the prodigious growth of this annual plant. The foliage is
often pitted by tiny holes that are made by flea beetles (the same species
that attack eggplant). The seeds can remain viable in the ground for
SEASONAL DEVELOPMENT: The blooming period occurs from mid-
summer to early fall and lasts about 2 months.
GENERAL DISRIBUTION: Jimsonweed is found throughout most
of North American with the exceptions of Wyoming in the United
States, and Newfoundland and the northern territories of Canada.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: The flowers are pollinated by Sphinx
moths. Various species of beetles are attracted by the flowers, especial-
ly at night, where they steal nectar and chomp on the pollen. The foliage
and its juices are consumed by flea beetles, aphids, psyllids, and other
small insects; their presence attracts ladybird beetles and other predatory
insects. The foliage and seeds contain an impressive assortment of toxic
alkaloids that can be fatal to mammalian herbivores and humans. Some
of these alkaloids are mildly narcotic and hallucinogenic. The immature
seeds are especially poisonous; as few as 20 seeds can fatally poison a
child. It is doubtful that birds make any use of these toxic seeds. Humans
help to spread the seeds around through activities that are related to agri-
culture, construction, and landscaping.
Crooked Run Valley