1 8( I CRUCIFERAE. 



Sili(|nc narrowly linear, elongated, terete or nearly so. 



Leaves coarsely toothed or some pinnatifid or entire; flowers white or yellowish. 



1. Thelypodium. 

 Leaves for the most part pinnatifid, or the lowest pinnately parted; flowers 



yellow 3. Sisymbrium. 



Silique compressed; valves more or less 1-nerved; flowers purple, white or nearly 



white 8. Arabis. 



Siliqne pointed, somewhat quadrangular, midrib of valve conspicuous; flowers 



rather small, bright yellow 9. Barbarea. 



Siliqne 4-sided or flattened; valves 1-nerved; flowers large, pale yellow or orange.. 



7. Erysimum. 

 Silique compressed, pointed. 



Stems sparingly leafy from a perennial, tuberous rootstock; flowers large, white 



to rose-tinted 11. Dentaria. 



Stems leafy; annual with fibrous roots and smaller flowers 12. Cardamine. 



Racemes leafy; silique obcompressed 13. Tropidocarptm. 



Seeds in 2 rows in each cell; silique terete, linear to oblong; flowers small (2 lines 

 long or less), white or yellow 10. Nasturtium. 



2. Pod a silicle, roundish or little longer than broad. 

 Silicle turgid, obovoid or pear-shaped; edges of the valves narrowly margined; flowers 



yellowish 15. Camelixa. 



Silicle much flattened contrary to the narrow partition and 



Obcordate or elliptical, several-seeded; flowers white or slightly yellowish 



14. Capsella. 

 Didymous, the valves separating as closed 1-seeded nutlets; flowers greenish-white.. 



19. Coronopus. 



Orbicular or ovate, more or less emarginately winged at summit; flowers white or 



apetalous 18. Lepidium. 



B. Pod indehiscent. 

 Pod elongated, breaking transversely into 1-seeded indehiscent joints. 



Pod several-seeded, commonly with constrictions between the seeds; flowers showy ... . 



6. Raphanus, 



Pod 2-jointed, breaking in the 'middle, each joint 1-seeded; flowers small 



4. Cakile. 

 Pod broader than long, more or less didymous, the cells indehiscent but separating from 



the axis when ripe 19. Coron'Tis. 



Pod wholly indehiscent, roundish or obovate. 



Pod ] to several-seeded, wingless 16. Athysanus. 



I'ocl 1-seeded, margined with a wing 17. Thysanocarpus. 



1. THELYPODIUM Endl. 

 Ours annual herbs. Flowers white or pale yellow (straw-colored), in often 

 dense racemes. Leaves mostly petioled, not auriculate or clasping. Petals 

 with narrow claw and linear or obovate exserted limb. Stamens tetradynamous, 

 ex sorted, with long and slender, never united filaments. Anthers narrowly 

 Linear, sagittate, curved. Stigma circular or obscurely 2-lobed, usually small. 

 Pod elongated, terete, sessile or short-stipitate. Seeds oblong, somewhat flat- 

 tened, not winged. Cotyledons incumbent. (Creek, thelus, female, and pus, 

 foot or support, the ovary more or less stipitate.) 



Cauline leaves mostly petioled; flowers 1 ]/ 2 to 2 lines long 1. T. lasiopkyllum. 



(.".-inline leaves sessile or the lower frequently petioled; flowers 4 to 5 lines long. 



Ovary glabrous; petals conspicuously exceeding the acuminate sepals.... 2. T. greenei. 



Ovary hairy; petals little exceeding the obtuse sepals 3. T. Havesctns, 



1. T. lasiophyllum Greene. Erect, simple or branching above, 1 to 3 ft. 

 high, hispid with scattered hairs or nearly glabrous above; Lower leaves sin- 

 uately pinnatifid With mostly acute denticulate or entire segments, 2 to 5 in. 

 the upper lanceolate, less Lobed or merely toothed, all petioled, or the 

 upper rarely sessile; flowers l'j or - Lines Long, closely clustered, white or yel- 

 lowish, on commonly curved pedicels I line Long; sepals oblong, scarcely more 

 than half the Length of the narrow petals j pods ascending or strictly deflezed, 



