MUSTARD FAMILY 
Io. 
The flowers of nearly all species of the Mustard 
family are characterized by 4 sepals, 4 petals arranged in 
the form of a cross, 6 stamens 2 of which are shorter than 
the other 4, and 1 pistil which in fruit becomes a pod. 
They are so much alike that it is frequently impossible to 
identify the plants by flowers alone; and the fruits, which 
often differ enough for purposes of identification, must 
then be used. 
The family is very important economically, as it con- 
tains, besides a number of weeds, many beautiful garden 
flowers and such vegetables as Cabbage, Cauliflower, 
Kale, Brussels Sprouts, Kohl-rabi, Mustard, Turnip and 
Radish. No plant in the family is poisonous, but leaves or 
roots, stems, and in some cases seeds, have a pungent odor 
or peppery taste. 
KEY TO GENERA 
Flowers yellow. . ov. o2.2.: 77. d0 5. U0 
Flowers white or purple. :..... ....... 2.13.0 ee 
Petals more than one-half inch long... .. 7...) O22 eee 
Petals shortef ..c. 0... 082204)... eee 
Flowers orange-yellow; leaves narrow...... Erysimum p. 
Flowers yellow; leaves broader.............. Brassica p. 
Flawers Bright “yellow... Ages Le. e6 ee: eee Barbarea p. 
Flowers pate yellow 2.0 0a. fs OS a: Sisymbrium p. 
Plants growing in brooks or streams.......... Radicula p. 
Plants not in.brooks or streams...) s. . <.... <4 Jee 
Fruits flat and short.) -. 002: .... 0.2... 2 ee 
Fruits elongated... . 2. ....../92 2... 2s. 4 ee 
Fruits nearly circular, up to one-half inch in diameter; 
seeds 2.or more in each cell. :)..00 5.45555 Thlaspi p. 
Fruits nearly circular, not more than one-eighth inch in 
diameter; seeds 1 in each cell........... Lepidium p. 
Pimits ttiamewlare as. co likes Ue te ee ee .Capsella p. 
Leaves palmately divided. 27.5. 00 es Dentaria p. 
Leaves not palmately divided. ¥ 2020s. +... S-ee 
Two of the sepals with a hump just below the tip........ 
NEE ee Mcp aaa cectend a a Palace BG tn Ty Todanthus p. 132 
Lower leaves nearly as broad as long, on long petioles.... 
eR RE Ow oon ep AGk a ha Uk See en ee ae Cardamine p. 134 
Lower leaves much longer than broad, on short petioles... 
SUN dated sa see pix eens Baie palette Echo na ee ee een Arabis p. 135 
CRUCIFERAE 
