I’m gonna be in the official plant record books!
According to Ken Klemow of Wilkes I’ve found a plant not found before in northeastern pa. if you open the link — if its openable — you’ll see where the plant has been found and never before in the northeastern part of the state.
I finally got freed up to look into your plant. I would agree that it is a Cardamine impatiens. The palmately lobed leaflets are good distinguishing characters. According to PA Flora (http://paflora.org/original/sp-page.php…), the species does not occur in northeastern PA. It is common near Philadelphia, and has scattered distribution in the northwestern and central parts of the state.
I walk the Back Mountain trail once every 6-8 weeks, and will need to bring a plant press next time.
By the way, I would be grateful if you could collect some plants for our herbarium if you would be willing. I could lend you a press or two.
It’s common name is narrowleaf bittercress.
[photo of flowers] Flowers are in rounded clusters averaging ½ inch across at the top of the plant and at the end of branching stems. Individual flowers are white to greenish, tiny with 4 petals but these are typically absent or indistinct.
Leaves and stem: Leaf attachment: alternate leaf attachment: basal Leaf type: compound Leaf type: lobed
[photo of stem leaves] There are both basal and alternate stem leaves. Stem leaves are compound in groups of 13 or more, to 6 inches long. Leaflets are generally lance to arrowhead-shaped, about 1 inch long with asymetrical bases; the edges may be smooth, jagged or sharply toothed.
[photo of leaf auricle] Where the leaf joins the stem are a pair of narrow, pointed lobes (auricles). When the leaf is detached from the stem the auricles remain.
[photo of basal leaves] Basal leaves are compound in groups of 3 to 11, with rounded lobes that may be further notched or lobed, and asymetrical bases. Leaves and stems are hairless. Flowering stems are usually produced the second year.
Fruit: Fruit type: capsule/pod
[photo of fruit] Fruit is a straight slender pod, erect to spreading, up to about 1 inch long. Ripened pods burst open and can shoot seed several feet from the mother plant, thus it can form dense colonies fairly quickly and crowd out native plants.
Narrow-leaf Bittercress may resemble some other Cardamine species, most notably Pennsylvania Bittercress, but the latter has larger and better defined flowers while the former has the distinct auricles at the leaf base. This is a new exotic species in Minnesota, and highly invasive. According to the MN Dept. of Agriculture, a single plant was discovered at Riverside Park in 2008; by 2009 they were pulling out truckloads of it. So far it has been found mostly in the Mississippi River Valley, and probably spreads via the river. At Battle Creek Park in St. Paul, it has been found along the dirt bike trails throughout wooded areas. It is very likely that weed seed is transported by bikers and dog walkers when they travel from infested to uninfested areas without cleaning their bike tires, footwear, or animal’s feet and coat. This is a continuing problem in the battle against invasive species—always clean your gear!