GENERA OR FAMILIES. 145 



4. Cistaceous Plants. CISTACE^:. 



(16) Helianthemum two outer sepals smaller ; petals deciduous 



capsule three-valved. 



5. Resedaceous Plants. HESEDACE^:. 



(17) Reseda flowers in racemes ; stamens indefinite, but not 



numerous, about 8-24, inserted on a glandular disk. 



6. Cruciferous Plants. CRUCIFER^.. 



* Fruit a silique or pod, linear or linear-lanceolate, usually 

 much longer than broad. 



t Pods two-valued, with a dissepiment. 

 Style not forming a stout conical ~beak. 

 Calyx conspicuously bisaccate at the base. 



(18) Matthiola pod round or compressed ; stigma sessile, two- 



lobed, the lobes erect, gibbous or horned at the back. 



(19) Hesperis pod quadrangular or sub-compressed, the valves 



keeled, somewhat three-nerved ; stigma nearly sessile, of 

 two closely-converging erect elliptical obtuse lobes. 



Calyx equal at the base, or very slightly gibbous. 



(20) Erysimum pod tetragonal, the valves prominently keeled, 



with one longitudinal nerve ; stigma obtuse, entire or 

 slightly emarginate ; seeds in a single row ; calyx erect. 



(21) Sisymbrium pod terete, or angled ; valves convex, with 



three longitudinal nerves ; stigma entire ; seeds in a single 

 row, smooth ; calyx spreading. 



(22) Nasturtium pod nearly cylindrical, short, the valves con- 



vex, almost nerveless ; stigma capitate ; seeds irregularly 

 in two rows. 



(23) Barbarea pod tetragonal, somewhat compressed, the valves 



convex, with a prominent longitudinal nerve ; stigma capi- 

 tate ; seeds in a single row 



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