16 
1. B. asperum DC. (WESTERN WALIL-FLOWER.) Minutety roughish hoary, stout, 
3 to6 dm. high, simple: leaves lanceolate to linear, entire or somewhat toothed : 
flowers crowded and showy, bright orange-yellow : petals orbicular, on very slender 
claws: pods nearly erect or widely spreading on short pedicels, elongated, 7.5 to 10 
cm. long.—Common in western Texas, along streams, on rocky bluffs and foothills, 
and on the plains. 
3. DRYOPETALON Gray. 
An annual or biennial plant, with runcinate clustered radical leaves, 
few and smaller stem leaves, many-flowered racemes crowded even in 
fruit, white flowers with petals lobed like a common oak-leaf, and very 
slender terete pods with sessile stigma and 3-nerved valves. 
1. D. runcinatum Gray. Stem 3to06dm. high, branching, glabrous: radical leaves 
7.5 to 10 cm. long, short-petioled, oblong or obovate, pubescent or villous, especially 
beneath; stem leaves successively smaller, not auriculate or dilated at base: petals 
6 mm. long, the limb incisely pinnatifid into 5 or 7 lobes, being one of the few mem- 
pers of this family with lobed petals.—In the mountains of extreme western Texas 
and northern Mexico. 
4. BRASSICA L. 
The B. Rapa L., or common turnip, seems to have escaped extensively 
from cultivation in Texas. It should at once be recognized by its rough 
lyrate radical leaves and characteristic roots. 
5. SISYMBRIUM Tourn. 
Pubescent annuals or biennials, with toothed or finely dissected leaves, 
very small yellow or white flowers, linear nearly terete pods, and oblong 
seeds. 
1. S. canescens Nutt. (TANSY MUSTARD. ) Leaves twice pinnatifid, often hoary 
or downy, the divisions small and toothed: flowers yellowish: pods in long racemes, 
oblong-club-shaped or oblong-linear.- -Throughout Texas, and one of the most com- 
mon of western mustards. 
2, S. diffusum Gray. Diffusely and divergently branching and canescent with 
minute pubescence: leaves oblong, obtuse, attenuate at base, sinuate-dentate or 
pinnatifid : flowers white, the petals scarcely longer than the sepals: pods in short 
racemes, almost subulate, scarcely thicker than their pedicels, canescent, tipped with 
a manifest style-—Growing on rocky ledges in the mountains of extreme western 
Texas. 
6. NASTURTIUM R. Br. (WATER-CRESS. ) 
Aquatic or marsh plants, usually glabrous, with commonly pinnate 
or pinnatifid leaves, yellow or white flowers, oblong-linear to globular 
pods, and strongly convex nerveless valves. 
* Petals white, twice the length of the calyx : pods linear : leaves pinnate: perennial. 
1. N. officinale R. Br. (TRUE WATER-CRESS.) Escaped from cultivation into 
brooks and ditches which it rapidly fills with its spreading and rooting stems: leaf- 
lets 3 to 11, roundish or oblong, nearly entire: pods 12 to 16 mm. long, ascending on 
slender widely spreading pedicels.—This native of Europe is said to have taken pesses- 
sion of most of the streams in western Texas. 
