CRUCIFEK^ 333 



XX. CRUCIFER^. Mustard Family. 



Herbs, mostly of small stature, with alternate mostly simple 

 leaves: flowers 4-merous as to envelopes, the four petals usually stand- 

 ing 90 degrees apart and thereby forming a cross (whence the name 

 Cruciferte, or "cross-bearing"): stamens usually 6, two of them 

 shorter: fruit a silique or silicle. A very natural or well-marked 

 family, with about 180 genera and nearly 2,000 species. Familiar 

 plants are mustard, shepherd's purse, honesty, cress, pepper-grass, 

 wallflower, stock, cabbage, turnip, radish, horse-radish. 



A. Fruit a silique (much longer than broad). 



B. Silique tipped with a long point or beak, extending 



beyond the valves, the latter more than 1-nerved. 1. Brassica 

 BB. Silique not prominently beaked beyond the valves. 



o. Flowers yellow 2. Barharea 



cc. Flowers white or purple. 



u. Valves with a midrib, or seeds in 2 rows. 



E. Stigma deeply 2-lobed: flowers large 3. Matfhiola 



EE. Stigma but slightly, if at all 2-lobed 4. Arabis 



DD. Valves without midrib. 

 E. Seeds in 1 row. 



F. Stems leafless below, with 2 or 3 leaves 



near middle: rootstock scaly 5. Dentaria 



FF. Stems leafy: roots more fibrous 6. Cardamine 



EE. Seeds in 2 rows in each cell. (Water plants. 

 See Nastiirfium). 

 AA. Fruit a silicle (short and broad). 



B. Partition in the pod parallel to the sides. 



c. Fruit not much compressed: seeds minute, in 2 



rows in each cell 7. Nasturtium 



CC. Fruit quite flattened, 2-8 seeded 8. Alyssum 



BE. Partition crosswise the pod. 



c. Pod obcordate, many-seeded 9. Capsella 



oc. Pod orbicular, 2-seeded: corolla regular 10. Lepidium 



ccc. Pod rounded or ovate: corolla irregular with un- 

 equal petals 11. Iberis 



AAA. Fruit fleshy, indehiscent, constricted between the 



seeds 12. Baphanus 



1. BRASSICA. Mustard. 



Erect branchy herbs, mostly annual, with more or less lyrate lower 

 leaves, and small yellow flowers in racemes or panicles: petals clawed or 

 narrowed below, the limbs spreading horizontally . silique narrow, cylindrical 

 or 4-angled, the valves 1-5-nerved and the seeds in 1 row in each locule. 



