The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

[++] Cotyledons accumbent.

11. Nasturtium. Pod often short; valves strongly convex, nerveless. Seeds small, in 2 rows in each cell. Flowers yellow or white.

12. Barbarea. Pod somewhat 4-sided; valves strongly 1-nerved. Seeds in 1 row. Flowers yellow.

[++][++] Cotyledons incumbent or partially so.

13. Hesperis. Pod terete, elongated; stigma-lobes narrow, erect. Flowers large, purple.

14. Erysimum. Pod 4-sided; valves strongly 1-nerved; stigma broadly 2-lobed. Pubescence of appressed 2–3-parted hairs. Flowers yellow.

15. Sisymbrium. Pod angled or teretish; valves 1–3-nerved; stigma small. Flowers yellow or white, small.

16. Thelypodium. Pod teretish; valves 1-nerved; stigma entire. Cotyledons obliquely incumbent. Flowers rose-color. Leaves auricled.

[++][++][++] Cotyledons conduplicate.

17. Brassica. Pod beaked or pointed beyond the end of the valves, or tipped with a rigid style, nearly terete, or 4-sided. Flowers yellow or whitish.