The short-stalked, gray-green leaves of field parsley piert are distinct for their three deeply-lobed segments at the tips, giving a unique, intricate appearance. They feature a wedge-shaped base, with bi-ternately lobed segments adding further complexity. Typically, leaves measure about 1 inch (2.5 cm) across. The texture is slightly rough, and the vein pattern is prominently visible, enhancing the overall detailed structure. This characteristic lobing and shape make the leaves easily identifiable.

Field parsley piert features tiny green flowers with four sepals and no petals, appearing in dense clusters within leaf axils. Each flower is surrounded by leaf-like stipules forming a cup. Measuring only a few millimeters across, these flowers bloom from April to September. Their compact, petal-less structure makes them distinct, with the sepals providing the main visible element. The green hue, diminutive size, and clustered formation are key identifiers for these flowers.

The stem of field parsley piert is many-branched and green, exhibiting a fine, slightly hairy texture. It is slender, measuring around 1-2 mm in thickness (0.04-0.08 inches). The branching pattern is intricate, with multiple branches emerging from the main stem at regular intervals, creating a dense and bushy appearance. The green coloration of the stem is consistent throughout, aiding in camouflage among foliage. This intricate branching and texture are key features for identifying the plant.

The fruit of field parsley piert is an oval pointed achene that is notable for its smooth, glabrous surface. This achene typically has a length of approximately 0.04 inches (1 mm), with a subtle brown coloring as it matures. Its small size and distinctive pointed shape, along with a lack of hairiness, are key identifying features. This dry, one-seeded fruit does not open to release its seed, a characteristic trait of the achene type. Its diminutive and simple structure is adapted for dispersal by various environmental factors.