18 COMMON CANADIAN WILD PLANTS. 



15. Nes'lia. Flowers very much as in the last. Pod nearly globular 



hardly one-twelfth of an inch across, usually only 1-celled and 

 1-seeded, wrinkled, tipped with the slender style. 



*- -*~Silicle compressed contrary to the narrow partition. 



16. Capsel la. Flowers white. Pod obcordate-triangular ; valves 



boat-shaped, wingless. Seeds numerous. Cotyledons incumbent. 



17. Tlilas pi. Flowerswhite. Podobovateorobcordate,tcznped. Seeds 



several. Cotyledons accumbent. 



18. Lepld'lum. Flowerswhite or whitish. Pod roundish, very flat; 



the valves boat-shaped and winged. Seeds solitary. 



19. Seneble'ra. Flowers greenish- white, very small. Pod 2-seeded, 



the valves wrinkled and separating at maturity as 2 closed one- 

 seeded nutlets. Prostrate diffuse herbs, with a disagreeable char- 

 acteristic odour. 



* * * Pod indehiscent, fleshy, jointed. 



20. Cakl'le. Flowers purplish. Pod 2-jointed, fleshy. Leaves fleshy. 



Cotyledons accumbent. 



21. Kaiili amis. Flowers yellow, turning whitish or purplish. Pod 



elongated, several-seeded, mostly constricted between the seeds. 

 Cotyledons conduplicate. 



1, NASTTR'TIIIM, R. Br. WATER-CRESS. 



1. N. Offleina'le, R. Br.. (WATER-CRESS.) Flowers white. 

 Stem spreading and rooting. Leaves pinnate ; leaflets 3-11, 

 roundish or oblong, nearly entire. Pods oblong-linear. 

 Ditches and streamlets. 



2. N. palus'tre, DC. (MARSH CRESS.) Flowers yellow. 

 Stem erect. Leaves pinnately parted, the lobes cut-toothed. 

 Pods ovoid. Wet places. 



3. N. laeus'tre, Gray. (LAKE CRESS.) Flowers white. 

 An aquatic plant, with the submerged leaves finely dissected ; 

 the leaves out of the water oblong, and either entire, serrate. 

 or pinnatifid. Pods ovoid, 1-celled. 



4. N. Armora'eia, Fries. (HORSERADISH.) Has escaped 

 from gardens in many places. Flowers white. Root-leaves 

 very large, oblong, and generally crenate ; stem-leaves 

 lanceolate. Pods globular. Roots very large. 



5. N. traehyear'pum, Gray. Flowers white. Stem 

 nearly glabrous, erect, branching. Leaves lyrate-pin- 

 natifid. Pods oblong-linear, somewhat roughened, soon 



