PLATE 10. 



PEPPERGRASS, Lepidium apdalum, Willd. 



Other Latin name: Lepidiuvi intermedium , Gray. 



Native. Annual and winter annual. Stems erect, profusely branching 

 above, 6 inches to 2 feet high, somewhat hoary, with short appressed hairs. 

 Autumn plants produce a rosette of dark green deeply indented leaves, 

 much like some specimens of Shepherd's-purse, but more succulent. Stem 

 leaves with a few coarse teeth, narrowed at the base. The many ascending 

 and spreading branches give this plant, when in seed, the appearance of a 

 miniature tree, the very numerous small nearly round flat pods taking the 

 place of leaves : the real leaves of the plant fall away early when the seeds 

 begin to ripen. Although there are only two seeds in each pod, a very large 

 amount of seed is produced by each plant. The flowers are minute, and the 

 seed pods about yV of an inch wide, heart-shaped, slightly longer than 

 wide, notched at the tip; these separate into two valves in the same way 

 as in the Stinkweed ; but in this plant there is only a single seed in each 

 valve. The seeds [Plate 53, fig. 7 — natural size, and enlarged 8 times] are 

 egg-shaped in outline, much flattened, blunt on one edge, and very thin at 

 the other, where there is a more or less apparent narrow wing ; each flattened 

 side shows a rather deep groove between the radicle and the seed leaves, ex- 

 tending three parts of the way up the centre of the seed from the base. The 

 basal scar of attachment is white, and projects somewhat from the outline 

 of the seed. The colour of the seed coat is bright reddish-yellow. The 

 wetted seeds give off a large supply of mucilage, the transparent hairs are 

 of medium length and fewer in number than in Shepherd's-purse and False- 

 flax. The embryo is incumbent, the radicle lying down the back of one of 

 the seed-leaves, which is the easiest character by which this species and its 

 close allies may be distinguished from the verv similar Lepidiuiv virginicnm. 

 This latter species, however, is very rare in Canada, and nowhere occurs as 

 a weed. 



Time of Flowering : June, July, seed ripe on early plants by the end 

 of June. 



P iopagatio7i : By seeds. 



Occurrence : Throughout the Dominion, but seldom complained of as a 

 weed in the East, except in clover in the clover-seed-growing districts of On- 

 tario, and in grain crops of the West, where it crowds out crops grown on 

 stubble, particularly on light land and in a wet spring. 



Injury: Peppergrass has frequently been the cause of considerable loss 

 in the West under the conditions mentioned above. This is from the autumn 

 grown plants which get a start before the grain crop and choke it out with 

 their thick vigorous growth. The seed is a frequent impurity in grass and 

 clover seed. 



Remcdg : Clearing laud of Peppergrass is an easy matter, because the 

 plants which do harm are those which germinate in the autumn. Disking 

 land in autumn nr early spring, before the new growth of roots takes place, 

 will clear it entirely of th's weed. If the work is not done earlv in spring 



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