48 
Colorado Agricultural College 
Fig-. 75. Indian Mus- 
tard (Brassica juncea). 
X 22. 
4. Indian Mustard (Brassica 
juncea (L.) Cosson.) (Fig. 75). — 
Seeds brick-red to wood-brown in 
color, usually covered with grayish 
bloom ; seeds spherical in shape, 
1.2-1.8 mm. in diameter, surface 
marked with a network of lines 
bordering pits, more shallow * than 
in B. nigra, but each pit covering 
a greater area, giving the network 
a distinct and coarser appearance. 
2. Peppergrass, Bird-seed 
(Lepidium L.) 
Pods either round or oblong, short; seeds mostly flat, grooved nearly 
their entire length. 
Key to Species 
Seeds flat 1..L. apetalum 
Seeds conical or cylindrical 2..L. campestre 
1. Peppergrass, Apetalous Peppergrass (Lepid- 
ium apetalum Willd.) (Fig. 76). — Seeds dull cinna- 
mon-rufous in color, each side marked with a distinct 
groove nearly the length of the seed; seeds often 
possess narrow, translucent, scale-like margins; seeds 
oval in shape, one extremity pointed, the other 
rounded, 1-1.7 mm. long, .6-.8 mm. across each face. 
Fig. 76. Pep- 
pergrass (Lepid- 
ium apetalum). A. 
Top view. B. Edge 
view. X 15. 
2. Field Cress, Cow Cress (Lepidium 
eampesP'e (L.) R.Br.) (Fig. 77). — Seeds 
dull, bone-brown in color, conical to 
cylindrical in shape, circular in cross- 
section, surface roughened with two shal- 
low grooves, meeting at the hiluni and 
forming an angle of 60° ; seeds rounded at 
one extremity, the other pointed, 1.7-2. 5 
mm. long, 1-1.5 mm. wide, in the widest 
Field Cress (Lepid- ti<iirt 
campestre). x 13. i ‘ • 
. Penny cress, Frenchweed, Wild Sweet Alyssum 
(Thlaspi (Tourn.) L.) 
Pods either circular in outline, oblong or wedge- 
shaped ; seeds 4-12 in each pod. 
Pennycress, Frenchweed (Thlaspi arvense //.) 
(Fig. 78). — Seeds dull black to oily black in color, each 
surface marked with 5-7 distinct concentric ridges con- 
verging at the hilum ; seeds flat, ovate in shape, one 
extremity rounded, the other pointed, 1.6-2 mm. long, 
1-1.5 mm. across each face at the widest part. 
Fig. 7 8. Pen- 
nycress (Thlaspi 
arvense). x 12. 
