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..
[Roripa Scop. Fl. Carn. 520. 1760.]
Branching herbs, with simple or pinnate lobed dissected or rarely entire leaves, and small yellow flowers. Sepals spreading. Stamens 1-6. Pods short, terete or nearly so. Stipe none. Valves nerveless or I-nerved. Style short or slender. Stigma 2-lobed or nearly entire. Seeds turgid, minute, in 2 rows in each cell or very rarely in 1 row. Cotyledons accumbent. [Name Latin, diminutive of radix, root.]
About 50 species, of wide geographic distribution, most abundant in the north temperate zone. Besides the following, there are about 12 other North American species, natives of the southern and western parts of the continent. Type species: Sisymbrium amphibium L.
Flowers and pods distinctly pedicelled; pods smooth or nearly so.
Leaves pinnately divided; style very short; naturalized European species.
Leaves pinnatifid; style slender; native western species.
Plants annual, biennial or perennial, with fibrous roots.
Fruiting pedicels \"-2" long; stem diffuse.
Pods linear to oblong, 3" - 5" long.
Pods subglcbcse, about I" in diameter.
Fruiting pedicels 2" - 4" long; stem erect.
Stem nearly or quite glabrous; pods linear or linear-oblong.
Flowers and pods very nearly sessile.
Sisymbrium sylvestre L. Sp. Pl. 657. 1753. Naslurtium sylvestre R. Br. in Ait. Hort. Kew. Ed. 2, 4: 110. 1812. Roripa sylvestris Bess. Enum. 27. 1821. Radicula sylvestris Druce, List Brit. Plants 4. 1908.
Perennial, glabrous; stems creeping, branches ascending. Leaves pinnately divided or deeply pinnatifid, petioled, 3'-5' long, 1'-2' broad, ovate in outline, the divisions obovate, or oblong, toothed or lobed, the terminal one often somewhat larger than the lateral; pedicels slender, 3" long; flowers yellow, 3"-4" broad; pod linear, 4"-6" long; style very short.