BRASSICACEAE. 149 



2. B. ochroleuca (Engelm.) Heller. Much like the last in habit, 

 but the flowers 2-2.5 cm. long, ochroleucous; only the tips of the 

 outer petals spreading; the inner with purple tips and with large 

 wing crest. {Dicentra ochroleuca Engelm.) 



Occasional on the northern slope of the Santa Monica Mountains. 



Family 38. BRASSICACEAE. Mustard Family. 



Herbs or rarely suffrutescent plants, with acrid juice, 

 alternate leaves and racemose or corymbose flowers. 

 Sepals 4, deciduous or persistent, the 2 outer narrow, the 

 inner similar, concave or saccate at base. Petals 4, 

 rarely 2 or none, hypogynous, cruciate, nearly equal, 

 generally clawed. Stamens 6, rarely fewer, hypogynous 

 tetradynamous. Pistil 1, compound, consisting of 2 

 united carpels, the parietal placentae united by a dis- 

 sepiment; style generally persistent, sometimes none; 

 stigma discoid or more or less 2-lobed. Fruit a silique 

 or silicle, usually 2-celled, 2-valved or rarely indehiscent. 

 Endosperm none; cotyledons incumbent, accumbent or 

 conduplicate. (Cruciferae.) 



* Pods dehiscent into 2 valves to the base, 

 a. Pods elongated-linear, at least twice as long 

 as wide. 

 Flowers white or purplish. 



Subaquatic or marsh plants. 



Seeds in 1 row in each cell. 13. Cardamine. 



Seeds in 2 rows in each cell. 11. Sisymbrium. 



Not aquatic or marsh plants. 



Rootstocks tuberous. 14. Dentaria. 



Roots fibrous. 

 Petals flat. 



Pods usually compressed, 



seeds flat, winged. 23. Arabis. 



Pods terete; seeds oblong or 



globose, wingless. 2. Thelypodium. 



Petals undulate-crisped or twist- 

 ed. 

 Pods terete or nearly so; 



cotyledons incumbent. 3. Caulanthus. 



Pods compressed; cotyledons 

 accumbent. 4. Streptanthus. 



Flowers yellow. 



Pods borne on a long stipe. 1. Stanleya. 



Pods sessile or short stipitate. 



