This plant is a herbaceous perennial that becomes 1¼–2½' tall when it
flowers. The central stem is light green, terete, sparsely hairy,
and unbranched. Alternate compound leaves occur primarily along
the lower one-half of this stem; they are odd-pinnate with 3-9 primary
leaflets (usually about 5). In addition to the primary leaflets, there
is usually a single pair of secondary leaflets on each compound leaf;
these secondary leaflets are much smaller in size. Successive pairs of
primary leaflets become gradually larger in size, while the terminal
primary leaflet is the largest in size, for each compound leaf. The
terminal primary leaflets are 2–3½" long and 1¼–2" across; all primary
leaflets are obovate to broadly ellipsoid in shape, while their margins
are coarsely dentate-crenate. The secondary leaflets are less than ½"
long and lanceolate to elliptic in shape. All of the leaflets are
The upper leaflet surface is medium green or yellowish green
and hairless (or nearly so), while the lower leaflet surface is light
or whitish green and sparsely hairy along the undersides of primary
veins. In addition, the lower leaflet surface usually has
minute glandular hairs that can glisten in bright sunlight (a 10x
hand lens may
be necessary to see them). The petioles and rachises of the compound
leaves are light green and sparsely hairy; they are flat or finely
grooved along their upper surfaces, while their lower surfaces are
convex. Pairs of stipules up to 1" long occur at the petiole bases of
compound leaves. These stipules are either unlobed and lanceolate in
shape, or they are divided into 2-3 lanceolate lobes. The central stem
terminates in either an unbranched raceme or sparingly branched racemes
of flowers. The racemes are spike-like in appearance and they are ½–1¼'
long. If lateral racemes are present, they are shorter than the central
raceme. The flowers are distributed alternately along each
raceme. Each flower is about ¼" across or slightly larger in size,
consisting of 5 yellow petals, 5 green sepals, 5-15 stamens, and a
burry green hypanthium containing a pair of carpels (female
reproductive organs). The rachis of each raceme is light to medium
green, terete, sparsely hairy below, and short glandular-hairy above.
The pedicels of the flowers are short (less than ¼" long).
period occurs from mid-summer to early autumn, lasting about 3 weeks.
There is no noticeable floral scent. The burry fruits (mature
hypanthia) are 3-4 mm. long and slightly less across; they are
obconic-hemispheric below, tapering to a knobby apex above. Around the
middle of each fruit, there are 2-3 rows of hooked spines
that are widely spreading to ascending (mainly the latter). The
obconic-hemispheric section of the fruit may have shallow longitudinal
grooves, or such grooves may be lacking. The entire fruit is covered
with very short glandular hairs. These fruits usually nod or hang
downward from their pedicels. Each fruit contains are pair of seeds.
The root system is fibrous, occasionally forming
narrow spindle-shaped tubers.
The preference is partial sun to light shade, mesic to
dry-mesic conditions, and soil containing loam, clay-loam, glacial
till, or rocky material.
The native Woodland Agrimony is
the southern half of Illinois and NE Illinois, while in the rest of the
state it is uncommon or absent (see Distribution
upland woodlands, upland savannas, rocky bluffs, and openings in upland
woodlands. This plant is found in higher quality natural areas.
The flowers are cross-pollinated by
other small bees, Syrphid flies, and other flies. Insects that feed
destructively on species of Agrimony (Agrimonia spp.
, larvae of
the gall fly Contarinia
, larvae of the sawfly Fenella
, and larvae of the moths Anacampsis agrimoniella
(Blackman & Eastop, 2013; Felt, 1917;
Smith, 2006; Covell, 1984/2005; Microleps website, 2010). There is some
evidence that White-tailed Deer browse on Woodland Agrimony (Agrimonia
), reducing its abundance in wooded areas
(Dávalos et al.,
2014). The burry fruits can cling to the fur of mammals (cattle, sheep,
deer), feathers of birds, and clothing of people, spreading the seeds
to new areas.
An opening in an upland woodland at Merwin
Nature Preserve in McLain County, Illinois.
The different species of Agrimony (Agrimonia spp.
spike-like racemes of small yellow flowers and compound leaves that are
odd-pinnate. Their compound leaves are unusual in having smaller
secondary leaflets interspersed between the larger primary leaflets.
Because they are similar in appearance, different species of Agrimony
can be difficult to identify. Woodland Agrimony (Agrimonia rostellata
can be distinguished from these other species of Agrimony by examining
its fruits: 1) its burry fruits tend to be smaller in size (3-4 mm.
long), 2) they have fewer bristles that are spreading to ascending, and
3) they are more hemispheric below and develop a knob-like beak above,
rather than being obconic below and with a more tapered beak above. In
addition to its fruits, Woodland Agrimony can be distinguished from
some species of Agrimony by the short glandular hairs on its floral
stalks, the scarcity of secondary leaflets on its compound leaves, the
presence of minute glandular hairs on the lower sides of its leaflets
be difficult to see), and its greater tendency to develop branching
racemes of flowers. Overall, Woodland Agrimony tends to be less robust
and smaller in size than other species of Agrimony within the state.