THALAMIFLOE^E. 



209 



CEOSS-FLOWEES. 

 Coh. Parietales, Benth. et Hook. 



Diagnosis. Herbs with a pungent watery juice, cruciform 4- 

 merous flowers, tetradynamous stamens, a siliquose or siliculose 

 fruit, and aperispermic seed. 



Character. 



Calyx: sepals 4, deciduous, imbricated or valvate in the bud. 

 Corolla: petals 4, distinct, stalked, arranged in the form of 

 a cross, alternating with the 

 sepals (fig. 346). Stamens tetra- Fig. 346. 



dynamous (fig. 347), a single 

 short one opposite each lateral 

 sepal, and a pair of long ones 

 opposite the anterior and the 

 posterior sepals, with small glands 

 intervening between the stamens 

 on the receptacle. Pollen gene- 

 rally ovoid, with three folds. 

 Ovary solitary, 2-celled by a spu- 

 rious dissepiment (replum) ex- 

 tending across from the middle 

 line of the two parietal placentas ; **%; '^ 

 stigmas 2, sessile, opposite the 



Fig. 349. 



Fig. 347. 



Fig. 347. Stamens and pistil of Chtnranthus. 



Fig. 348. Ground-plan of the flower of Cheiranthu : x, the front ; O, the position of the axis. 



Fig. 349. Burst sihque of Sinapia. 



