VOL. II.] 



MUSTARD FAMILY. 



123 



16. IODANTHUS T. &G.; A. Gray, Man. 32. 1848. 



A glabrous erect perennial herb, with dentate leaves auricled at the base, or the lower and 

 basal ones lyrate-pinnatifid, and violet or white flowers in panicled racemes. Sepals much 

 shorter than the petals, the inner ones slightly gibbous at the base. Petals long-clawed. 

 Style stout; stigma subcapitate. Silique linear-cylindric, somewhat constricted between the 

 seeds. Seeds oblong, rounded, in i row in each cell. Cotyledons accumbent. [Greek, 

 violet-colored flower.] 



A monotypic genus of southeastern North America. 



i. lodanthus pinnatifidus (Michx.) Steud. lodanthus. Purple or False 



Rocket. (Fig. 1712.) 



Hesperis (?) pinnalifida Michx. Fl. Bor. 



Am. 2: 31. 1803. 

 lodanthus hesperidoides T. & G. ; A. 



Gray, Gen. 111. i: 134. 1848. 

 Thelypodium pinnatifidum S. Wats. Bot. 



King's Exp. 25. 1871. 

 lodanthus pinnalifidus Steud. Nomencl. 



Ed. 2, 812. 1841. 



Glabrous, stem slender, i-3 high, 

 branching above. Lower leaves ovate 

 or oblong (occasionally cordate), 2'- 

 8' long, dentate, tapering into a mar- 

 gined petiole which is clasping and 

 auriculate at the base, the lower part 

 of the blade often pinnatifid into 2-6 

 pairs of small oblong segments; stem- 

 leaves similar or merely dentate, nar- 

 rower, sometimes ovate-lanceolate, the 

 upper nearly sessile; flowers numerous, 

 3 // -4 // broad; pedicels spreading, 2"- 

 3" long in fruit; pods linear, i / -i^ / 

 long, y?." wide, spreading or ascend- 

 ing; style stout, \" long. 



On river banks, western Pennsylvania 

 to Minnesota, south to Kentucky, Louisi- 

 ana and Texas. May-June. 



17. RORIPA* Scop. Fl. Cam. 520. 1760. 

 [NASTURTIUM R. Br. in Ait. Hort. Kew. Ed. 2, 4: 109. 1812.] 



Branching herbs, with simple or pinnate lobed dissected or rarely entire leaves, and yel- 

 low or white flowers. Sepals spreading. Stamens 1-6. Pods short or elongated, terete or 

 nearly so. Stipe none. Valves generally i -nerved. Style short or slender. Stigma 2-lobed 

 or nearly entire. Seeds turgid, minute, in 2 rows in each cell (very rarely in i row). 

 Cotyledons accumbent. [Name unexplained.] 



About 25 species, of wide geographic distribution, most abundant in the north temperate zone. 

 Besides the following, there are about 5 other North American species, natives of the southern and 

 western parts of the continent. The white- flowered species perhaps represent different generic types. 

 Flowers yellow. 



Flowers and pods distinctly pedicelled. 



Plants perennial by creeping or subterranean branches. 



Leaves pinnately divided; style very short; naturalized European species. 



i. R. sylvestris. 



Leaves pinnatifid; style slender; native western species. 2. R. sinuata. 



Plants annual or perennia_l, with fibrous roots. 

 Pods i "-5" long, straight. 



Fruiting pedicels i"-2" long; stem diffuse. 



3. R. obtusa. 



4. R. sphaerocarpa. 



Pods linear to oblong, 3-5" long. 

 Pods subglobose, about i" in diameter. 

 Fruiting pedicels 2" -4" long; stem erect. 



Stem nearly or quite glabrous ; pods linear or linear-oblong. 5. R. palustris. 

 Stem hispid-pubescent; pods globose or oval. 

 Pods 4" -7" long, strongly curved upward. 

 Flowers and pods very nearly sessile. 

 Flowers white. 



Leaves pinnately divided; pods linear. 



Leaves simple or the lower pinnatifid; pods oblong or globose. 



Terrestrial, tall; leaves crenate, or the lower lobed or pinnatifid. 

 Aquatic; immersed leaves finely dissected. 



6. R. hispida. 



7. R. curvisiliqua. 



8. R. sessiliflora. 



9. R. Nasturtium. 



10. R. Armoracia. 



11. R. Americana. 



* Originally spelled Rorippa, but corrected to this form by Adanson in 1763. 



