State Status: Pennsylvania Endangered (PE)
PBS Status: Pennsylvania Endangered (PE)
Global Rank: G5
State Rank: S1
Cross-leaved Milkwort is an herbaceous annual with a hairless, more-or-less 4-sided stem that may grow to 30 cm in height, but is usually shorter. The leaves are arranged in whorls of 3 or 4, unstalked, linear to narrowly elliptic in shape, untoothed on the margin, and to 4 cm in length and to 3 mm in width. The greenish or greenish-purple flowers, appearing from July to September, are individually small and are aggregated in a dense, apically rounded, barrel-shaped cluster, which has at most a very short stalk, at the end of the stem or the branches of the stem. The most notable parts of the individual flower are the 2 inner sepals, which are larger and shaped differently from the 3 outer sepals and the 3 petals, being broadly-triangular in outline, heart-shaped at the base, and long-pointed at the tip. The fruit is a dry capsule containing 2 seeds.
Critically imperiled in the nation or state because of extreme rarity (often 5 or fewer occurrences) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.
It grows in damp or wet openings, bogs, shorelines, and marshes.
Flowers late July - September
Cross-leaved Milkwort ranges from Maine to Minnesota and south into Florida and Texas. In Pennsylvania, it has been documented historically in the southeastern and southwestern counties.
The viability of populations of Cross-leaved Milkwort and its habitat may be enhanced by creating buffers and protecting the natural hydrology around wetlands and controlling invasive species.
Conservation Status Map
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org.
- NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available at https://www.natureserve.org/explorer
- Pennsylvania Natural Heritage Program. 2018.
- Rhoads, A.F. and W.M. Klein, Jr. 1993. The Vascular Flora of Pennsylvania. American Philosophical Society, Philadelphia, Pennsylvania. Rhoads, A.F. and T.A. Block.
- 2007. The Plants of Pennsylvania: An Illustrated Manual. 2nd edition. University of Pennsylvania Press, Philadelphia, Pennsylvania.