Thlaspi arvense
Field pennycress is a widespread introduced plant. It has been documented in every state except Alabama and Hawaii (USDA, 2014). This plant is common to disturbed sites and also invades many newly planted ornamental and crop sites.
It is a member of the mustard family and has an annual life cycle. The small white flowers occur in clusters towards the end of the flowering stem. As with all mustards, each flower has four petals. As the plant matures it produces relatively large round flat seeds and as the plant cures it typically turns yellow. The leaves clasp the stem, have a light colored midrib, and have a toothed margin. The stem has prominent veins. It has a very simple shallow taproot.
Parts of field pennycress are edible and it is being investigated as a potential bio-diesel candidate as the seeds are oil rich and mature early in the season.
Field pennycress is commonly confused for the noxious weed, whitetop. Although there are some similarities in appearance – whitetop is a perennial, with a complex root system. Whitetop has a round stem and the entire plant is covered with many fine hairs. They also produce very different seeds.
USDA, NRCS. 2014. The PLANTS Database (http://plants.usda.gov, 18 March 2014). National Plant Data Team, Greensboro, NC 27401-4901 USA.
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