BRASSICACEAE 483 
l. Leavenworthia aurea Torr. Foliage glabrous. Stems erect or decumbent, 
4-15 em. long, often branched at the base: leaves mainly basal, a few on the stems ; blades 
divided into 5-9 angular-toothed segments, the terminal one largest: pedicels 1-4 cm. 
long, ascending, often curved : sepals oblong, 3.5-4 mm. long, obtuse: petals yellow, or 
purplish with a yellow base, twice as long as the sepals, narrowly cuneate, retuse at the 
apex: pods linear-oblong, not torulose, 1.5-2 cm. long, each tipped with a slender style 
1-2 mm. long: seeds-4-14: cotyledons orbicular, cordate ; radicle straight. 
On rocks, Arkansas to Tennessee, south to Alabama and Texas. 
2. Leavenworthia unifldra (Michx.) Britton. Foliage glabrous or nearly so. 
Stems 2-15 cm. long, erect or ascending, simple or sparingly branched: leaves mainly 
basal, 2-10 em. long ; blades divided into 5-17 unequal toothed or angular segments, the 
terminal one ‘larger than the rest: pedicels 2-15 cm. long, erect or ascending: sepals 
oblong, obtuse : petals white or purplish, with a yellow base, cuneate-oblanceolate, retuse at 
the apex: pods linear-oblong, 2.5-3.5 cm. long, each tipped with a stout style 1 mm. 
long : seeds 4-18: cotyledons oval; radicle oblique. [L. Michauxii Torr. ] 
In dry soil, Indiana to Missouri, Tennessee and Alabama. 
3. Leavenworthia stylósa A. Gray. Foliage glabrous. Stems 2-12 cm. long, as- 
cending or prostrate : leaves mainly basal, 2-8 cm. long ; blades divided into 3-7 entire or 
angular segments, the terminal one much larger than the rest: pedicels ascending, 4-10 
cm. long : sepals oblong, about 5 mm. long, obtuse : petals yellow, emarginate, about twice 
as long as the sepals: pods oblong, 4-8 mm. long, each tipped with a slender style 4-6 
mm. long, not torulose : seeds 6-8: cotyledons oval; radicle oblique. 
In cedar woods, Tennessee. 
4. Leavenworthia torulósa A. Gray. Foliage glabrous. Stems 2-15 cm. long, 
erect or ascending, sometimes almost wanting : leaves mainly basal, 2-10 cm. long; blades 
pinnately-divided into entire angled or lobed segments, sometimes represented by a large 
terminal segment and two small lateral ones: pedicels erect or ascending, 4-10 cm. long: 
sepals narrowly oblong, 5 mm. long, obtuse: petals purplish, with a yellow base, nearly 
twice as long as the sepals, emarginate: pods linear, 2-3 cm. long, conspicuously con- 
stricted below between the seeds, each tipped with a slender style 2-3 mm. long: seeds 
4-14: cotyledons oval ; radicle oblique. 
In wet soil, cedar barrens, Kentucky and Tennessee. 
23. ARABIS L. 
_ Annual or perennial herbs, with glabrous or glaucous foliage, or pubescent with fork- 
ing or stellate, or rarely simple hairs. Leaves alternate, sometimes mainly basal : blades 
entire, toothed or pinnatifid. Flowers perfect, in terminal or axillary racemes. Sepals 
4, equal or nearly so, sometimes saccate at the base. Corolla white, pink, purple or yellow- 
ish : petals 4, entire or emarginate, often with claws. Stamens 6: filaments free, unap- 
pendaged. Ovary sessile : stigma capitate or 2-lobed. Ovules numerous. Pods elongated, 
flat, the valves sometimes nerved or keeled, not dehiscent. Seeds in 1 row in each cavity, 
marginless, margined or winged. Cotyledons accumbent or incumbent. Rock CRESS. 
Basal leaves with pinnatifid blades. ? 
Sepals 1-2 mm. long: seeds winged. 
Pods 2-2.5 cm, long, the valves obscurely nerved'at the base: seeds narrowly winged. 
1. A. Virginica. 
Pods 5-7.5 cm. long, the valves nerved below the middle: seeds broadly winged. 2. A. petiolaris. 
Sepals 2-2.5 mm. long : seed 
Basal leaves with toothed blades. eo 3 ui 
s wingless. Ad T 
8 winged or margined. 
Capsules erect or nearly so, sometimes appressed. 
Corollas over 7 mm. broad : capsules not appressed : style 1 mm. lon 5. A 
Corollas less than 7 mm. bn " g fe ie. . A. hi 1 
Ca ules recurved. broad : capsules appressed : stigma sessile. 6. A. hirsuta. 
ants glabrous, glaucous : pods 1-2 mm. wide. 7. A. laevigata. 
Plants pubescent, at least below: pods 2.5-3.5 mm. wide. 8. A. nikah. 
po Arabis Virgínica (L.) Trelease. Annual or biennial, sparingly hirsute or nearly 
y P nos Stems usually branched at the base, the branches ascending or decumbent, 1-4 
A simple or branched : basal and stem-leaves quite similar, 2-7 cm. long ; petioles 
alei gi than the blades, margined ; blades deeply pinnatifid into uniform entire or 
$6 Maas: nearly oblong or linear segments: pedicels finally spreading or ascending, 
9.95 m. rudi sepals narrowly oblong, 1 mm. long, obtuse: petals white: pods linear, 
[A tabs long, straight, ascending or somewhat spreading: seeds in 1 row, winged.. 
s viciana, (Hook. ) C. A. Meyer.] 
In sandy or rocky soi], Virginia to Missouri, Florida and Texas. Spring. 
