GENUS 36. 



MUSTARD FAMILY. 



189 



36. LEAVENWORTHIA Torr. Ann. Lye. N. Y. 4: 87. 1837. 



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 i 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 i. L. uniflora. 



Pods constricted between the seeds. 2. L. torulosa. 



i. Leavenworthia uniflora (Michx.) Britton. Michaux's Leavenworthia. 



Fig. 2097. 



Cardamine uniflora Michx. Fl. Bor. Am. 2: 29. 1803. 

 Leavenworthia Michauxii Torr. Ann. Lye. N. Y. 4 : 89. 



1837- 

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



Tufted, 2'-6' high. Basal leaves rosulate, numerous, 

 i '-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"-is" 

 long, 2" wide when mature; style stout, about \" long. 



In open dry places, southern Indiana to Missouri and 

 Tennessee, west to Missouri. April. 



2. Leavenworthia torulosa 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, ii"-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. 



37. SELENIA Nutt. Journ. Acad. Phila. 5: 132. 1825. 



Annual tufted glabrous herbs, with pinnatisect leaves, and racemose leafy-bracted yellow 

 flowers. Sepals spreading. Petals narrow, erect, with 10 hypogynous glands at their bases. 

 Silique stalked, very flat, oblong, narrowed at each end. Valves nerveless, thin, finely veined, 

 dehiscent. Style long, slender. Seeds few, in 2 rows in each cell of the pod, orbicular, flat, 



