16 DIALYPETALOUS EXOGENS 



DIVISION 1. SILIQUO V SAE. 



Fruit a silique i. e. a slender elongated jointless pod. or capsule of 2 valves, ren- 

 dered 2-celled by a false septum, or partition, etretched between the parietal placen . 

 toe, from which the valves separate. 



TRIBE 1. ARABID'EAE. 



Seeds compressed, sometimes margined ; cotyledons plane, parallel with the septum, 

 accumbent (o =) i. e. with their edges to the radicle. 



28. NASTUR/TIUM, R. Br. 



[Latin, Nasus tortus, a convulsed nose ; from its pungent effect.] 

 Silique rather short and turgid, usually curved upwards. Seeds ir- 

 regularly in 2 rows in each cell, not margined. 



1. N. offitinhle, R. Br. Stem radicating; leaves odd-pinnately di- 

 vided, with rounded or oblong segments. 

 OFFICINAL NASTUKTIUM. Water-Cress. 



Perennial. Stem, 6 to 12 or 18 inches long, branching. Leaves dissected into 3 

 to 7 or 9 segments, the terminal one largest. Petals white. 

 Hob. Rivulets, and ditches. Nat. of Europe. Fl. June. Fr. July. 



Obs. This foreign plant which is the true Water- Cress, of Eu- 

 rope was found (in 1838, since the publication of the preceding 

 edition), near Downingtown, by Mr. JOSHUA HOOPES. It is easily 

 propagated, and is now naturalized in several localities in the 

 County. Being a wholesome Salad, it deserves to be generally in- 

 troduced into suitable springs and brooks, for table use. 



29. CARDAM'ItfE, L. 



[Gr. Kardamon ; an ancient name for Cress.] 



Silique linear, flattened; valves nerveless, usually opening elastically 

 from the base. Seeds in a single row in each cell, not margined. 



f BIENNIAL : leaves pinnatifid ; flowers small. 



1. C. llirsilta, L. Smoothish; stem erect; leaves pinnately dis- 

 sected or lyrate-pinnatifid, segments of the lower ones rounded, of 

 the upper ones lance-oblong. 



HIRSUTE CARDAMINE. Common Bitter-Cress. 



Stem 3 or 4 to 12 or 18 inches high, branching, and often several from the same 

 root. Leaves 1 to 3 or 4 inches long> petiolate. Racemes 2 to 4 or 6 inches long. 

 Petals white, narrow, twice as long as the calyx, but rather inconspicuous. 

 Hob. Springs, and swampy rivulets : frequent. Fl. May. Fr. June. 



Obs. Our plant is usually so much less hairy than the European 

 one of the same name, that it has been regarded as a distinct species, 

 by many botanists, and called C. Pennsylvanica. 



f f PERENNIAL : leaves nearly entire ; flowers conspicuous. 



2. C. rottmdifolia, MX. Stem weak and decumbent, with 

 creeping runner-like branches; leaves all orbicular and petiolate; 

 root fibrous. 



ROUND-LEAVED CARDAMINE. American Water-Cress. 



Stem 6 to 12 or 15 inches long, with slender procumbent axillary branche?. 

 Leaves all similar in form, the lower ones about two inches long, sometimes with 

 a pair of small lobes on the petiole, the upper leaves gradually smaller as they 



