CRUCIFERAE 



MUSTARD FAMILY 



FIELD PENNYCRESS. MITHRADATE MUSTARD 



Thlaspi arvense L. 



The Field Pennycress is a smooth annual which is not 

 common in the southern part of the state but becomes more 

 frequent farther north and in Canada is often a pernicious weed. 

 It is a native of Asia and Europe and 

 from the latter was introduced into 

 this country. It blooms from June to 

 September. 



This plant grows in fields, roadsides 

 and waste places, is 6-18 inches high 

 and usually somewhat branched above, 

 though frequently simple in colonies. 

 The basal leaves are petioled but they 

 soon disappear and then all the leaves 

 are like those shown, oblong or lanceo- 

 late, slightly dentate and sessile by 

 arrow-shaped bases. They are alternate 

 as in all Mustards. 



The numerous small flowers are 

 white, each of the 4 petals being about 

 one-eighth of an inch long. There are 

 6 very short stamens and a single pistil 

 with a flattened ovary, which in fruit 

 becomes enlarged to a diameter of one- 

 half inch and is distinctly winged. This 

 pod is longitudinally divided, with 2-8 

 seeds in each half. 



Wild Peppergrass or Birdseed, Lepi- 

 dium virginicum L., is a very common smooth annual ot yards and 

 waste places alike. It grows up to i foot high and becomes much 

 branched as the season advances. The leaves are variable, the 

 obovate or spatulate basals having large terminal lobes and small 

 lateral ones, and the small, very numerous and linear or lanceolate 

 stem leaves are more or less toothed and sessile. The small white 

 flowers are born at the summit of elongating racemes. Stamens are 

 1. The flat round fruits are notched at the apex, about one-eighth 

 inch across, and have 1 cells each containing i seed. Seed-eating 

 birds like the fruits. Illinois is well within the range of this plant, 

 which is from Quebec to Minnesota, south to Florida, Texas and 

 Mexico. The blooming season is June to September. 



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