ORDER XIII. CRUOIFERJE. 223 



Order XIIL— CRUCIF'ER^S. (Mustard Family.) 



Sepals 4, deciduous, cruciate ; aestivation generally imbri- 

 cate. Petals 4, cruciate, alternating with the sepals. Stamens 

 6, tetradynamous ; the two shorter lateral, occasionally toothed, 

 inserted lower than the others. Disk often with small green 

 glands inserted between the petals and the stamens and ovari- 

 um. Ovary 1-celled, consisting of two carpels, with two pari- 

 etal placentae, which are reflected into the cavity, where they 

 unite and form a false dissepiment. Stigma opposite the dis- 

 sepiments (a remarkable variation.) Fruit a silique or silicle, 

 2-celled, produced by the spurious dissepiment mentioned 

 above ; one or many seeded. Seeds campylotropous, attached 

 in a single row to each side of the placentae. Herbaceous 

 plants, with a watery and generally with an acrid juice, form- 

 ing Class XIV. of the Linnsean system. 



ANALYSIS. 



1. Fruit linear, a silique 2 



Fruit nearly as broad as long, a silicle 8 



2. Seeds arranged in two rows in each ceil Nasturtium, 1 



Seeds in one row in each cell 3 



3. Silique 4-cornererl Erysimum, 7 



Silique terete or flat 4 



4. Flowers purple or pink Warea, 8 



Flowers while 5 



Flowers yellow 7 



5. Silique lanceolate, flowers in terminal racemes Dentaria, 4 



Silique linear 6 



6. Siliqne curved, long Arabia, 2 



Silique straight, flowers small Cctrdamine, 3 



7. Silique terete, tapering appressed to the stem Sisymbrium, 6 



Silique oblong, linear,"compressed, few-seeded Leavenworthia, 5 



Silique ensiforni, or nearly terete Sinapis, 10 



8. Silicle oval, oblong Draba, 12 



Silicle reniforra Coronopus, 13 



Silicle emarginate Capsella, 15 



9. Silicle cordate Lepidium, 14 



Silicle 2-jointed, somewhat 4-angled Cakile, 16 



Genus I.— NASTUR'TIUM. R. Br. 14— 2. {Cresses.) 

 (From the Latin nasus tortus, convulsed nose, from its pungent qualities.) 



Silique nearly terete, sometimes resembling a silicle, usually 

 curved. Stigma 2-lobed. Sepals spreading. Seeds arranged 

 in two series, minute, destitute of margins. Found in wet 

 places. 



1. N. officinale, (Brown.) Leaves pinnately divided ; segments 

 ovate, eub-cordate, repand. Petals longer than the calyx. — White. 

 Introduced. 



2. N. tanacetifo'lium, (Hook.) Stem much branched, diffuse. Leaves 

 pinnately divided, lobes sinuate or toothed, obtuse, smooth. Flower* 



