This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Acad. 4: 6. 1849. Corydalis aurea var. occidentalis Engelm.; A. Gray, Man. Ed. 5, 62. 1867. Capnoides aureum var. occidentale A. S. Hitchcock, Spring Fl. Manhattan, 17. 1894. Capnoides montanum Britton, Mem. Torr. Club 5:
Closely resembles C. aureum, but is lighter green and the leaves are rather more finely divided. Flower-clusters spicate-racemose, the pedicels usually very short; flowers bright yellow, 6"-8" long; spur of the corolla as long as its body, or less; capsules spreading or somewhat ascending; seeds sharp-margined, shining or obscurely reticulated.
In dry soil, South Dakota to Kansas, Texas, Utah and Mexico. Perhaps a race of the preceding species. April-Aug.
Capnoides campestre Britton, Man. Ed. 2, 1065. 1905.
Similar to the two preceding species, Flowers spicate-racemose, about 8" long, conspicuous, bright yellow; spur of the corolla blunt, nearly straight, 2"-2 1/2" long; pods curved upward, very short-pedicelled, stout, somewhat 4-sided; seeds sharp-margined, finely and distinctly reticulated.
Corydalis crystalline Engelm.; A. Gray, Man. Ed. 5, 62. 1867. Capnoides crystallinum Kuntze, Rev. Gen. Pl. 14. 1891.
Erect or ascending, glabrous, 8-20' high, branching. Lower leaves slender-petioled, the upper sessile, all finely dissected into oblong or cuneate segments.; pedicels stout, short, diverging; flowers spicate, 6"-8" long, bright yellow; spur 3"-4" long; crest large, dentate; capsules 9" long, ascending or erect, densely covered with transparent vesicles; seeds acute-margined, tuberculate-reticulated.