- Allegheny Hawkweed (Hieracium paniculatum)
- Kalm’s Hawkweed (Canada Hawkweed) (Hieracium kalmii)
- Common Hawkweed (Hieracium lachenalii)
- Maryland Hawkweed (Hieracium marianum)
- Robinson’s Hawkweed (Hieracium robinsonii)
- Rough Hawkweed (Hieracium scabrum)
- Narrowleaf Hawkweed (Hieracium umbellatum)
Kalm’s Hawkweed has a lower stem and underside of leaves with long hairs. In most pictures, it appears that the flower stem grows a foot or more above the stem leaves and the flower stems do not droop much. The Kalm’s Hawkweed leaves look a bit like my pictures except they are shorter and wider (proportionally).
Common Hawkweed has mostly larger basal leaves with 4-7 sessile stem leaves. The 2-1/2 foot tall stem is topped by 4-12 yellow flowers in a round-topped cluster. Flower heads have white hairs around the base (like Robinson’s Hawkweed). The leaves of Common Hawkweed have larger teeth than this plant.
This left me with a description of Allegheny Hawkweed that closely matched the pictures and an online image from florafinder.com that looks just like this plant:
Largely solitary stems (up to 3 feet tall) with stem leaves up into the inflorescene and few to no basal leaves. The stem is mostly hairless (ocassional hairs). The leaves are papery thin and have an irregularly-tooth margin (few teeth). The underside of the leaves are slightly whitened. The inflorescense at the top contains up to 20 flowers on thin, flexible and mostly hairless peduncles (flower stalks). The flowers are up to 1.5 cm (3/5 inches) wide, while those of other hawkweeds can be up to 1 inch wide. The smaller flowering heads, slender and flexible flower stalks and papery thin and mostly hairless leaves are distinguishing characteristics.
