158 CRUC1FER.-E. 



nearly even lines. Seeds 4 to 8 on each placenta, horizon- 

 tal, or toward the summit pendulous, forming two rows in 

 each cell, orbicular, flat, surrounded by a firm and rather 

 broad wing, the cavity extended into a kind of pouch or 

 CEecum next the hilum on the lower or placental side, into 

 which the embryo does not extend. Cotyledons orbicular, 

 flat, parallel with the partition, accumbent against the radi- 

 cle, which is very short and ascending, or nearly horizon- 

 tal, on the side remote from the placenta. 



Herb annual or biennial, low, smooth, branching from the 

 base, leafy, terminated by racemes of pretty large, yellow 

 flowers ; the leaves runcinate-pinnatifid : the filiform pedicels 

 subtended by foliaceous bracts like the leaves. 



Etymology. From o-(\i)vr), the moon ; a name chosen to express the near 

 relationship of the genus to Lunaria. 



Geographical Distribution. Only one species is known (unless the 

 form with the partition obsolete should prove distinct), which grows in damp 

 prairies of Arkansas and the adjacent part of Texas. 



Note. The areolae of the partition are said to be linear and transverse 

 by Torrey, in Ann. Lye. Nat. Hist. New York, 3. p. 94, and in the Flora of 

 North America, 1. c. (which would lie like those of Lunaria rediviva) ; but 

 in our specimens, which, however, all belong to the variety with an incom- 

 plete partition to the pod, they are seldom more than oblong, and in great 

 part oblique or vertical, as represented at fig. 7. The singular pouch just 

 below the hilum gives to the seed so exactly the appearance of being resu- 

 pinate, as in Cremolobus, that it was thus described in the Flora of North 

 America, 1. c, and a distinct tribe accordingly established for its reception. 

 But the radicle lies on the other side, as shown in our analyses ; and the 

 genus therefore belongs to Alyssinese, next to Lunaria. 



PLATE 67. Selenia aurea, Nutt.; — var. with the partition of the pod 

 incomplete, natural size ; from Arkansas, Dr. Leavenworth. 

 1. A sepal ; and 2, a petal, enlarged. 



3. Stamens and pistil, enlarged. 



4. Pistil, more magnified (the glands not well represented). 



5. Silicle, of the natural size, transversely divided. 



6. The replum and seeds, enlarged. 



7. Tissue from the imperfect partition, highly magnified. 



8. A seed, enlarged. 



9. Same, with the integuments cut away to show the embryo in place. 



10. An enlarged seed, transversely divided. 



11. The embryo detached entire, enlarged. 



