panicled tick trefoil (Desmodium paniculatum)
Hedysarum paniculatum L.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of panicled tick
trefoil is Desmodium paniculatum (L.) DC. Among different populations
of panicled tick trefoil, there is significant variation in the width of the
leaflets and the hairiness of the stems and leaflets. Usually, this wildflower
has fairly narrow leaflets, hairless to nearly hairless stems, and hairless up-
per surfaces on the leaflets. It can be distinguished from other species in
this genus by considering the following key characteristics: 1) the narrow
leaflets are 3-6 times longer than they are across, 2) the petioles of the tri-
foliate leaves are fairly long (up to 2"), 3) the deciduous stipules of the tri-
foliate leaves are small and insignificant, and 4) the leaflets are rather long
(up to 3½"). Panicled tick trefoil is one of a dozen species of Desmodium
reported occurring in Facquier Coutny.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This native perennial wildflower is 2–3½' tall, sometimes branch-
ing in the upper half. The stems are light green and usually hairless; how-
ever, some variants of this species have pubescent stems.
Leaves: Alternate compound leaves occur at intervals along the stems;
they are trifoliate and their leaflets are extended horizontally in relation to
the ground. Individual leaflets are up to 3½" long and ¾" across; they are
3-6 times as long as they are wide. Some variants of this species have
more narrow leaflets than others. The terminal leaflet is the same length
or a little longer than the lateral leaflets. The leaflets are elliptic to oblong
in shape and smooth along their margins. Their upper surfaces are medium
green and glabrous, while their lower surfaces are pale to medium green
and covered with appressed white hairs. The petioles of the compound
leaves are up to 2" long, light green, and mostly hairless. At the base of
each petiole, there is a pair of tiny deciduous stipules that are linear-lance-
olate; these stipules soon wither away. The petiolules (secondary petioles)
of the lateral leaflets are very short (1/8" or less), while the petiolules of
the terminal leaflets are longer (up to ½").
Flowers: The upper stems terminate in either racemes or narrow panicles
of flowers. The branches of each inflorescence are light green and covered
with hooked hairs. Individual flowers are ¼" long (or a little more), con-
sisting of 5 petals, a short tubular calyx with teeth, an ovary with a single
style, and several hidden stamens. The flowers have a typical pea-like
structure, consisting of an upright banner and 2 lateral wings that enclose
a central keel. The petals are pink to rosy pink; at the base of the upper
petal (banner), there are 1-2 tiny patches of yellow. The green calyx is
covered with hooked hairs. The slender petioles of the flowers are about
½" long; they are green to reddish purple and also covered with hooked
hairs. There is no noticeable floral scent.
Fruit/Seeds: Fertile flowers are replaced by flat loments (a type of seed-
pod) that are about ½–1½" long. Each loment consists of 2-6 rounded seg-
ments, a short stipe, and sometimes a short beak. Each segment of a lo-
ment is more rounded along the bottom than along the top; it contains a
single seed. The loments are covered with hooked hairs.
Roots: The root system consists of an elongated caudex with fibrous
roots. This wildflower spreads by reseeding itself.
REGENERATION PROCESS: Panicled tick trefoil propogates
itself by reseeding.
HABITAT TYPES: Habitats consist of thinly wooded bluffs, rocky open
woodlands, sandy open woodlands, sandy savannas and typical savannas,
woodland edges, thickets, rocky glades, and partially shaded roadside em-
bankments. This wildflower is a pioneer species that prefers some disturb-
ance from wildfires, selective logging, and others causes.
SITE CHARACTETRISTICS: Panciled tick trefoil prefers partial sun,
mesic to dry-mesic conditions, and sandy or rocky soil.
SEASONAL DEVELOPMENT: The blooming period occurs from
mid-summer to early fall and lasts about 1–1½ months.
GENERAL DISTRIBUTION: Panicled tick trefoil is primarily a
species of the eastern United States and Canada. It is found in Florida
north through New England and into Quebec and Ontario (but not the
Canadian maritime provinces), and extends west to Texas north to Ne-
braska. It does not naturally occur in the northern Great Plains of the
United States or Canada, the far southwest, Rocky Mountain region,
the far west and northwest regions of the United States or Canada.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Long-tongued bees collect pollen from
the flowers; these relatively uncommon floral visitors include bumble-
bees (Bombus spp.), leaf-cutting bees (Megachile spp.), and digger bees
(Melissodes spp.). Other insects feed on the leaves, flowers, and seeds of
Desmodium spp. (Tick Trefoils). For example, the caterpillars of several
skippers feed on the leaves: Achalarus lyciades (hoary edge), Epargyreus
clarus (silver-spotted skipper), Thorybes bathyllus (southern cloudy-
wing), and Thorybes pylades (northern cloudywing). The caterpillars of
the butterfly Everes comyntas (eastern tailed blue) also feed on the
foliage, while the caterpillars of the butterfly Strymon melinus (gray
hairstreak) eat the flowers and developing seedpods. These insect feeders
include many kinds of beetles, and some species of thrips, aphids, moth
caterpillars, and stinkbugs. The seeds are eaten by some upland gamebirds
(bobwhite quail, wild turkey) and small rodents (white-footed mouse,
deer mouse), while the foliage is readily eaten by white-tailed deer and
other hoofed mammalian herbivores. The cottontail rabbit also consumes
the foliage. The sticky seedpods (loments) cling to the fur of animals and
the clothing of humans. As a result, the seeds are carried to new locations.
Crooked Run Valley