Agrimonia gryposepala (Tall Hairy Agrimony)
|Also known as:||Tall Agrimony, Common Agrimony, Tall Hairy Groovebur|
|Habitat:||part shade; moist to dry soil; open woods, woodland edges, thickets, fields, banks, swamps|
|Bloom season:||June - September|
|Plant height:||1 to 5 feet|
|Wetland Indicator Status:||GP: FAC MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Elongating spike-like racemes at the top of the stem and arising from upper leaf axils. Flowers are ¼ to about 1/3 inch across with 5 oval yellow petals and 5 to 10 yellow stamens, the tips yellow to orange. Alternating with the petals are 5 green sepals that are pointed at the tip, sparsely hairy and slightly shorter than the petals.
Surrounding the base is a calyx-like structure known as a hypanthium, narrowed to a stalk-like base, with 4 or 5 rows of hooked bristles in a ring around the tip and a leaf-like bract at the base. Flowers are ascending to spreading at flowering time, mostly alternate and often widely spaced, especially on the lower part of the cluster. Stalks, sepals, bracts and the hypanthium are all densely covered in short glandular hairs with a few sparse, long, non-glandular hairs.
Leaves and stem:
Leaves are compound with 3 to 9 major leaflets (5 to 7 on mid-stem), and 1 to 4 pairs of small leaflets in between the larger ones. The end leaflet is largest, 1 to 4 inches long, ½ to 2 inches wide, becoming smaller towards the base of the compound leaf. Leaflets are elliptic to somewhat diamond-shaped, mostly widest near or above the middle, coarsely toothed with blunt to pointed teeth.
At the base of the leaf stalk is a pair of leafy appendages (stipules), those on mid-stem each broadly ½ heart to egg-shaped in outline, up to ¾ inch wide, and coarsely toothed around the edge. The upper surface of leaflets and stipules is hairless or nearly so, the lower densely covered in short, glandular hairs with sparse, long, non-glandular hairs mostly along the veins, and a fine fringe of hairs along the edges.
Stems are stout, mostly erect, branched, and densely covered in short, glandular hairs mixed with long, spreading, non-glandular hairs, the non-glandular hairs denser on the lower stem and more sparse in the flower clusters.
The hypanthium becomes nodding and enlarges to about ¼ inch long at maturity, the base usually bowl to bell-shaped, with 10 grooves. The surface is densely covered in short, glandular hairs with sparse long, non-glandular hairs near the base and sometimes on the ridges between the grooves, but not in the grooves. The sepals persist and become erect, forming a beak at the tip. The rows of hooked bristles spread out, the top row becoming erect and the lowest row distinctly bent downward (reflexed). Inside are 1 or 2 seeds.
There are 3 Agrimony species in Minnesota, all of which have similar leaves, flowers and fruit. Tall Hairy Agrimony is probably the easiest to recognize from the dense covering of short, glandular hairs mixed with sparse long, spreading non-glandular hairs on both stems and leaf undersides. On mature fruit, the bottom row of bristles is distinctly reflexed and there are scattered long, non-glandular hairs near the base of the hypanthium and sometimes on the ridges, but none in the grooves. The glandular hairs can be seen with the naked eye but a hand lens is helpful. By comparison, the other 2 Agrimonia species have a mix of long and short non-glandular hairs on stems, have more densely hairy leaves especially on major veins, their hypanthiums are hairy in the grooves and the lowest row of bristles is sometimes slightly reflexed but usually not. While many references note differences in the hypanthium shape of the 3 species, this is often a really subtle distinction so we tend to ignore it.
Even though this species is the most easily recognized Agrimonia in Minnesota, there is still plenty of confusion and the MN distribution map should be taken with a grain of salt. The DNR's MNTaxa distribution does not include more than half the counties which have herbarium records for A. gryposepala. Coincidentally(?), they list a number of these same counties for A. striata, but there are no corresponding herbarium records. We can't know for certain what's what without reviewing the actual specimens, but some are likely mis-IDs. So look for the glandular hairs on the stems to separate these two.
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- Tall Hairy Agrimony plant
- Tall Hairy Agrimony plant
- glands and hairs on leaf underside
- scan of leaf
- close-up of fruit
- more flowers
- more flowers
- comparison of MN Agrimonia species upper stem hairs
- comparison of MN Agrimonia species stipules
Photos by K. Chayka in Carlton and Ramsey counties. Photos courtesy Peter M. Dziuk taken in Cass County and his backyard garden in Ramsey County.
Have you seen this plant in Minnesota, or have any other comments about it?