Ball Mustard (Neslia paniculata (L.) Desv.).

Description. An erect, slender annual or biennial, 1-3 ft. high with stem simple up to the inflorescence; stem and leaves, both being covered with stellate pubescence; sessile leaves oblong, very

FIG. 91-C. Ball Mustard (Neslia paniculata); a, flowering stem; b, pod; c, seed. (Schuyler Mathews in Mich. Agr. Exp. Sta. Bull.)

narrow, sagittate at base; racemes elongate; flowers small, yellow, about 1 in. in diameter; seed-pods nearly spherical, 2-celled with 1 small yellow seed in each cell, sometimes but one developing.

Distribution.-In grain fields, Canada, the Dakotas and occasionally in northwestern Iowa.

Extermination.-Clean seed; easily destroyed by cultivation.

Hedge Mustard (Sisymbrium officinale (L.) Scop.).

Description.-A slender, erect annual or winter annual, 12-22 ft. high; lower leaves divided, upper entire or hastate at base; flowers small, yellow, borne in spikelike racemes; seeds small, brown; cotyledons incumbent.

Distribution.-Found everywhere in the state, notably in Story, Boone, Polk, Clinton, Linn, Marshall, Hardin, Black Hawk, Woodbury, Pottawattamie, Carroll, Jasper, Monroe, Scott, Lee, and Allamakee counties.

Extermination.-Easily exterminated by cultivation; also by using the formula 100 pounds of iron sulphate to one barrel of water.

Fig. 92. Hedge Mustard (Sisymbrium officinale). Common in gardens, fields and waste places.

(General aspect of plant photographed by Hart. Drawing by Charlotte M. King.)

Chemical Composition.—According to the University of Minnesota it is as follows:*

Description.-A leafy, branched annual from 1-4 ft. high, lower leaves runcinate, pinnatifid, irregularly toothed, or wavy margined, upper leaves smaller, threadlike.

Distribution. This weed is native to east Europe. It has become widely scattered in the northern states, particularly in the west from Minnesota to Washington and in Canada. It is widely scattered in Iowa in the vicinity of railroad watering tanks, elevators and stockyards. It is less common in the southern half of the state.

Extermination.-The young mustard plants are easily killed by cultivation. They are likely to occur in some commercial seed like timothy, therefore, sow only clean seed.

*Snyder: Bull. Minn. Agr. Exp. Sta., 101.

Fig. 93. Tumbling Mustard (Sisymbrium altissimum). In grain fields, rail

ways, etc.

Fig. 93-A. Distribution of Tumbling Mustard,

Marsh Cress (Radicula palustris (L.) Moench.).

Description.-An annual or biennial; erect, smooth, or slightly pubescent herb; from 1-12 ft. high; leaves pinnately cleft or parted, pinnatifid; the lobes toothed; upper leaves sessile; flowers yellowish in racemes; pods ellipsoid or ovoid.