About Corydalis micrantha (Engelm. & A.Gray) A.Gray ex J.M.Coult.
Corydalis micrantha (Engelm. & A.Gray) A.Gray ex J.M.Coult. is a species in the genus Corydalis, a genus that contains approximately 300 species. This species is divided into three accepted subspecies: C. micrantha ssp. micrantha, C. micrantha ssp. australis, and C. micrantha ssp. texensis. This species is an annual forb or herb. Morphological details differ across the three subspecies. For C. micrantha ssp. micrantha, plants form a basal leaf rosette about 8 inches across, and produce several flowering stalks around 8 inches long. Basal leaf blades can reach 3 inches long and 2 inches across; these leaves are pinnately compound, hairless, and range in color from dull green to greyish blue. Each flowering stalk ends in a flower raceme up to 3 inches long. Flowers have short pedicels and small bracts. Normal-flowered racemes do not grow much longer than the leaves, and are often short. Flower spurs are spherical at the tip. Fruits are typically firm and measure 10–15 mm long. Each flower has a corolla made of two outer petals that range from yellow to pale yellow, and two whiter, membranous inner petals. Habitats for this subspecies include open rocky woodlands, sandy savannas, ledges along lightly wooded bluffs, glades, gravelly areas alongside railroad tracks, and mulched areas around buildings. It prefers habitats with sparse ground vegetation and partial shade, and it is native to the central United States. For C. micrantha ssp. australis, normal-flowered racemes often grow much longer than the leaves. Flower spurs are not globose at the tip, and fruits are slender and measure 15–30 mm long. Erect pedicels are typically 2–5 mm long and 1–3 mm wide. The flower corolla is light yellow, and spurred petals measure 9–15 mm long. The fruit capsule is erect and has a cylindrical body around 15–20 mm long. Seeds are approximately 1.5–2 mm broad and lack a marginal ring. Leaves are green, sometimes glaucous; stems branch from the base, and leaves are pinnately decompound. This subspecies typically grows from March to April, and is most often found on sandy roadsides and fields, and is very rare on rocky slopes and mountains. It ranges from south-central to southern United States, and is currently listed as an endangered species in Illinois. For C. micrantha ssp. texensis, stems are typically firm, and become strongly striated when dried. Foliage ranges in color from green to bluish-grey, and produced fruits measure 25–30 mm long. This subspecies is found only in coastal south Texas. The full species Corydalis micrantha occurs primarily in the United States, where it has been recorded in Alabama, Arkansas, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Louisiana, Minnesota, Missouri, Mississippi, North Carolina, Nebraska, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, and Wisconsin.
