Low winter-annual glabrous scapose herbs, with lyrate-pinnatifid basal leaves, and few or solitary terminal flowers. Petals wedge-shaped. Siliques flat, broadly linear or oblong, short-stipitate; valves dehiscent, nerveless, finely reticulate-veined. Seeds in 1 row in each cell of the pod, flat, winged or margined; embryo straight, or nearly so, the redicle short, slightly bent toward the cotyledons. [In honor of Dr. M. C. Leavenworth, U. S. A.]

A genus of about 4 species, natives of southeastern North America. Type species: Leaven-worthia aurea Torr.

Pods not constricted between the seeds

1.

L. uniflora.

Pods constricted between the seeds.

2.

L. torulosa.

1. Leavenworthia Unifl˛ra (Michx.) Britton. Michaux's Leavenworthia

Fig. 2097

Cardamine uniflora Michx. Fl. Bor. Am. 2: 29. 1803. Leavenworthia Michauxii Torr. Ann. Lyc. N. Y. 4: 89.

L. uniflora Britton, Mem. Torr. Club 5: 171. 1894.

Tufted, 2'-6' high. Basal leaves rosulate, numerous, 1'-4' long, the segments 5-17, irregularly dentate or angled, 2"-3" long, the terminal one somewhat larger, all narrowed near the base, but slightly expanded at the junction with the rachis; stem-leaves none, or 1-3, similar, but smaller; flowers about 3" broad; petals white or purplish with a yellow base, about twice the length of the sepals; pods oblong or linear, 6"-15" long, 2" wide when mature; style stout, about i" long.

In open dry places, southern Indiana to Missouri and Tennessee, west to Missouri. April.

1 Leavenworthia Unifl Ra Michx Britton Michaux s L 4391 Leavenworthia Unifl Ra Michx Britton Michaux s L 440

2. Leavenworthia Torul˛sa A. Gray. Necklace Leavenworthia

Fig. 2098

Leavenworthia torulosa A. Gray, Bot. Gaz. 5: 26. 1880.

Closely resembles the preceding species, but the pods are narrower and distinctly constricted between the seeds. Style conspicuous, 1 1/2"-2" long; seeds sharp-margined, barely winged; terminal segment of the basal leaves decidedly broader and larger than the lateral ones; petals notched.

Barrens of Kentucky and Tennessee. April.